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The object of this little work is to present in an orderly 
manner a complete root-canal technic which is giving a large 
percentage of successful results in the writer's practice. The 
facts and theories set forth comprise a digest of the vari- 
ous methods advocated by the authorities, modified and 
supplemented by considerable study and some original 
research. Much of the matter included has already been 
made public in papers and clinics, but it is hoped that by 
thus gathering together in a consecutive manner the pro- 
cedures which have been most helpful to me, it may be pos- 
sible for others by comparison, to clarify their own technic. 

The subject will be treated in the following order: Diag- 
nosis, Asepsis, Instrumentation of the Canal, Therapy, 
Bacteriology, Obliteration of the Canal, and Surgery. 

It will be impossible at this time to give due credit for the 
many suggestions which have influenced me in arriving at 
this technic. Rhein. Callahan, Buckley, Coolidge, Ottolengui, 
Black, Prinz, Grieves, Moffit, McLean, and a host of others 
are the masters to whom the reader will owe any benefit 
which may be derived from a perusal of these pages. 

Before proceeding, let it be understood that the writer 

advocates the retention of the minimum number of non-vital 

teeth, and then only when these are necessary to preserve an 

unbroken arch, or to afford retention of prosthetic appliances. 

A. B. C. 
Washington. D. C. 1920. 


Introduction 17 


Diagnosis 20 


Asepsis 41 

Instrumentation of the Canal .... 50 


Therapy 65 


Bacteriology 81 

Obliteration of the Canal .... 89 


Surgery 104 



In view of the divergence of opinion of the acknowledged 
leaders of dental thought, there prevails in the average mind 
an uncertainty as to the efficiency of any method of dealing 
with pulpless teeth. While the medical profession in general 
contemplates with scepticism the attempts to retain non- 
vital teeth in situ, the natural repugnance of most patients 
to submit to the mutilation of extraction places the burden 
of responsibility squarely upon the dentist. 

The happy day may come when universal prophylaxis will 
practically eliminate the necessity for root-canal work, but 
the dentist of today must be prepared to render intelligent 
service to patients with diseases of the dental pulp. He must 
elect either to extract at once all teeth with exposed or non- 
vital pulps and absolutely avoid devitalization, or he must 
develop his root-canal technic to a point which will insure 
the patient, to a reasonable degree* against future extraction. 

The claim that no infected tooth can be retained with 

safety is as absurd as the attempt to save all teeth. There 

are men in every part of the country who can present an 

avalanche of roentgenographic and clinical evidence of bone 




regeneration in periapical areas previously infected. The 
writer and others have determined by occasional cultural 
tests through the alveolus that such regenerated areas are 
commonly sterile. 

The question, then, is not one of feasibility but ability, 
and the reason dentists generally are not making such teeth 
safe is because they will not devote the infinite attention to 
detail which this work demands. 

^Yhoever has followed the progress of root-canal technic 
during the past few years must be gratified by the tendency 
toward standardization of methods among the recognized 
leaders. In spite of occasional diatribes against the wisdom 
of retaining pulpless teeth, the writer believes that the prob- 
lem of a satisfactory root-canal therapy is nearing a solution. 
Although the hopelessness of the reorganization of patho- 
logical periapical areas can be logically set forth, the fact 
remains that actual cures are being daily effected. The pages 
of surgical history are illumined by the narration of the over- 
coming of other seemingly insurmountable difficulties. 

In 1552, at the siege of Danvillers a shot passed through 
the tent of M. de Rohan, and hit the leg of one of his retainers. 
One of the most famous surgeons of all time finished cutting 
it off, to the wrath of his contemporaries, refusing to use 
either the red-hot irons or the boiling oil, then considered 
indispensable. Pare was ridiculed, but the simple treatment 
of wounds and the ligation of arteries which he taught, with 
slight modifications, are fundamental to the surgery of today. 

In 1864, sepsis following surgical operations was con- 
sidered inevitable. In defiance of all tradition, Lister by 
scientific deduction evolved the true theory of antisepsis. 
The wise men of the times who prided themselves upon 
the number of old blood stains on their operating coats 


condemned his work as dangerous procedure, but to the 
great underlying truth of his theories is due the aseptic 
surgery of today. 

In 1915, in France, a wounded soldier is brought into a 
hospital. A wound in the leg, suppurating, contused, full 
of bits of shrapnel, dirt and pieces of clothing, has caused 
an alarming elevation of temperature. Logical surgical 
tradition would call for the amputation of this leg, but 
thanks to the scientific bravery of Carrel, in a few weeks 
this man is back on the firing line. 

Before Pare, the treatment of gunshot wounds without 
the use of hot oil and hot iron was impossible; before Lister, 
deliberate surgical operations without subsequent sepsis 
intervening were impossible; before Carrel, the closure of a 
suppurating wound in four days was impossible. 

Perhaps in dentistry, also, the seemingly impossible may 
be accomplished. The treatment of periapical disease may 
yet be placed upon such a scientific basis that none will 
question its expedience. Great men like Callahan may go to 
their graves with the condemnation and destructive criti- 
cism of the wise men ringing in their ears, but this problem 
will never be solved by the man who throws up his hands. 

Vincent, of Carrel's group, found that only about 30 per 
cent, of surgically aseptic wounds were bacteriologically 
aseptic. Yet thousands of soldiers who owe their lives to 
Carrel and Dakin would laugh to scorn the critic who con- 
demned their treatment on that account. So while the 
hypercritical pro-extractionists continue to prove that it is 
impossible to render an infected tooth and its environs 
bacteriologically aseptic, perhaps we, too, may depend upon 
the natural resistant forces to exert the same influence 
in the alveolus which contributes to the cure of infections 
elsewhere in the body. 


The foundation principle of a practicable root-canal 
technic is accurate diagnosis. Diagnosis is a scientific 
determination or discrimination of diseases by their symp- 
toms. It calls for a knowledge of cause and effect acquired 
only by a wide clinical observation. It is the embodiment 
of experience. 'Without a correct perception of conditions 
to be met any treatment becomes empirical. 

In the management of root-canals a careful diagnosis 
based upon methodical examination should precede any 
effort at treatment. Thereby much time and useless effort 
may be saved, and respect for the prognosis of the dentist 

The diagnostic procedure should begin with a thorough 
physical examination. If this is properly conducted it will 
not only indicate suspicious teeth, but in many instances 
will classify those which may be expected to respond favor- 
ably to therapeutics, those whose only hope lies in surgery, 
and those which must be condemned to extraction. 

The following conditions if found indicate the advis- 
ability of further investigation: 

Color. — A tooth whose shade is not in harmony with its 
fellows is probably the seat of a pulp lesion. 

Translucence. — This is commonly called the live-tooth 
appearance. When it is absent the pulp is probably dead. 


A small mouth lamp held lingually will be of graat assistance 
in determining this point. 

Large Cavities. — These should be carefully excavated and 
tested with a sharp explorer to determine proximity to 
the pulp chamber. 

Large Fillings — These are always suspicious, and should 
never be passed without thorough tests. 

Gold Crowns. — Teeth under gold crowns are also always 
suspicious. The wonder is not that so many pulps die in 
such teeth, but that any survive. The reason for this is that 
the freshly denuded dentin is left exposed to the fluids of 
the mouth until the crown or inlay is set. Infection invades 
the dentinal tubuli, and is sealed in to continue its activity 
until at last the pulp becomes infected. As a precautionary 
measure a mild antiseptic should be sealed in contact with 
exposed dentin before the patient is dismissed. Cement 
should be used in cavities and aluminum shells for crowns. 
A cement of eugenol and oxid of zinc is excellent for this 

Post Crowns. — With rare exceptions these are placed on 
pulpless teeth. 

Crownless Teeth. — These sometimes contain vital pulps, 
but unless treated prior to restoration will surely cause 



Having marked all teeth which are suspicious by the fore- 
going tests, they should be further checked by means of 
the electric current. Either the Faradic or galvanic current 


may be used* the only requirement being some method of 
controlling the dosage. The high-frequency current is also 
useful in this connection, but it is more difficult to concen- 
trate this current upon given areas of the tooth crown, and 
thus a faulty diagnosis may result. With any of the stand- 
ard galvanic switchboards, such as are used for electrolytic 
medication, the test is made as follows: 

A section of a broken broach is fitted into the needle- 
holder and attached to the positive wire. The sponge 
electrode is soaked with salt water and held by the patient 
in the palm of the hand. The tip of the broach is wrapped 
with cotton fibers, and this also is moistened with salt water. 
Several teeth which are unquestionably vital are now tested, 
and the tolerant dosage noted. With this as a control the 
suspicious teeth are tested. Machat warns against touching 
the electrode to metal fillings or crowns, but as the resistance 
of sound enamel varies so much in individual teeth, it is 
generally satisfactory to apply the electrode to a filling or 
crown where the metal does not come into contact with 
the soft tissues, especially where corresponding fillings or 
crowns on teeth of known vitality can be had as controls. 

It should be borne in mind that more current is required 
to penetrate enamel than metallic fillings, also that crowns 
and inlays have an intermediary of more or less non-con- 
ductive cement, which causes these teeth to respond only 
to an increased dosage. Recession of the pulp or thick 
deposits of secondary dentin in the pulp chamber must also 
be taken into consideration. When the canal is filled with 
the liquid products of decomposition, the tooth is often quite 
as sensitive to electricity as if the pulp were vital, and where 
hyperemia of the pulp exists, the tooth will often be more 
sensitive than the control. For teeth in which the electro- 


diagnostic test is inconclusive the old-fashioned thermal 
tests will often be of assistance in clearing the diagnosis. 

Having by the foregoing tests excluded the teeth of 
unquestionable vitality, the next step is a clinical examina- 
tion of the periapical region. Careful search should be made 
for fistula? or scars where these have healed. The discovery 
of such will suggest more or less destruction of periapical 
tissue, but there will often be as much or more disorganiza- 
tion where this evidence does not exi-t. 


The degree to which the apical attachments of the tooth 
have been destroyed may be judged by percussion. The 
so-called "dull note" of the older practitioners requires a 
trained ear. but has a definite value. The percussion test 
of Talbot is of more universal utility. This is accom- 
plished by placing a finger of the left hand over the apex of 
the suspected root and striking the cusps of the tooth with 
a heavy instrument at different angles. If the bone has 
undergone destruction the vibrations will be transmitted 
through the root to the finger. This test is of greater value 
on anterior teeth than on molars; where pyorrhea exist- it 
is utterly confusing. 

To ascertain the extent to which the bony plate of the 
alveolar process has been destroyed, take a small hard 
pledget of cotton in the cotton pliers, and press hard on the 
mucous membrane overlying the root apex. The tissue s will 
sink into such an opening, and slowly return when pressure 
is removed. The appearance is much the same as pitting 
of the skin by pressure in edema. 

Whenever the clinical tf-t- classify any tooth as suspicious, 


the patient should be carefully questioned as to its history. 
Some patients have extremely good memories, and almost 
all can remember a prolonged toothache or the swelling of 
the face in the region of the tooth in question. 


With the data now in hand all teeth recorded as non-vital 
or suspicious should be radiographed to complete the diag- 
nosis. Correct interpretation of dental radiographs cannot 
be made in the absence of good clinical data, and this point 
cannot be made too strong. Neither can radiographs be 
properly read by one deficient in the knowledge of normal 
dental anatomy. The density of the film, the angle from 
which the exposure has been made, the density of super- 
imposed structures, and the contiguity of other anatomical 
formations must all be taken into consideration. 

In reading a dental x-ray film, the teeth known to be normal 
should first be studied (Fig. 1). The use of a good reading- 
glass, or dentiscope, will be of great help. It will be noted 
in the case of a normal tooth that the pericementum can be 
traced around the root as a continuous radiolucent line. 
Adjacent to and surrounding this will be seen the lamina 
dura or radiopaque line. It will also be noted that the 
trabecule of bone about the apex are homogeneous with the 
bone which lies adjoining. 

Infection is microscopical, and cannot be radiographed. 
'What we look for in the film is not infection, but the results 
of infection. Thus it may happen that a tooth recently 
infected or one long the habitat of organisms of low virulence 
may present a radiographic record in no way differing from 
the normal (Fig. 2). Again, in the entire absence of infection 



there may be a rarefying process in the adjacent bone suffi- 
cient to cause a most decided radiolucent area. This latter 

Fig. 1. — The cuspid is normal. Note the continuous line of the peri- 
cementum and the lamina dura. Also the homogeneity of the surrounding 
trabeculse of bone. Compare with apical regions of lateral and first bicuspid. 

picture is caused by overstimulation, as in traumatic occlusion 
(Fig. 3) or orthodontic procedure, and may also be observed 
about the forming roots of adolescence (Fig. 4). Bearing 

Fig. 2. — Infected cuspid, with no radiographic evidence of periapical 
disturbance. Streptococcus. 

these points in mind, the suspicious tooth should be examined 
to see in what manner it differs from the normal. 



The first thing to look for is a thickening or break in the 
line of the pericementum at the apex of the root. Next 
the bone about the apex should be examined for radio- 

Fig. 3. — Radiolucent area about apex of second bicuspid, caused by 
traumatic occlusion. Pulp vital and normal. 

parency or radiolucency, and the presence or absence of the 
lamina dura noted; then the periphery of the apex should 
be studied for evidence of roughness. When any or all of 
these signs are recorded in the radiograph of a tooth which 

Fig. 4. — Note radiolucent area about root apices of first molar. 
Pulp normal. 

the clinical examination has shown to be non-vital, we may 
safely conclude that the tooth is infected, and that we are 
dealing with periapical disease. ^Yhere all of these signs are 


absent, and the pulp is known to be contaminated or dead, 
the infection, if present, while confined to the root-canal and 
dentin, is still a constant menace to the periapical tissues. 

At this point we are enabled to make a differential diagnosis 
and the tooth in question must be placed in one of the 
following classes : 

A. Pulp normal. 

B. Pulp exposed, but not infected (rare). 

C. Pulp exposed and infected. 

D. Pulp undergoing decomposition. 

E. Pulp non-vital, but no periapical disturbance. 

F. Pulp non-vital, with periapical disease. 


A comparative study of radiographs with the actual con- 
dition of the tissues, as disclosed by numerous root-resections, 
has led me to the conclusion that in periapical disease we are 
dealing with three distinct conditions, which may in most 
cases be differentiated in the film. For the sake of con- 
venience I have differentiated these conditions as follows 
(Fig. 5): 

Class I. Circumscribed radiolucent areas. (Primary 
granuloma) . 

Class II. Diffuse radiolucent areas. (Advanced granu- 

Class III. Circumscribed radioparent areas. (Dental 
cyst.) (Figs. 6 and 7). 

The outstanding characteristics of these three classes are 
as follows : 

Class I (Fig. 6, A) : Circumscribed Radiolucent Areas. 
— At first glance this may disclose no abnormality of the 



Class I. Class II. Class III. 

Fig. 5. — 1, circumscribed radiolucent area (granuloma); II, diffuse radiolucent 

area (granuloma); III, circumscribed radioparent area (dental cyst). 

Class I. 

Class II. 

Class III. 
Fig. 6. 


Periapical disease. Class I. Note Periapical disease, Class II. Note 

circumscribed radiolucent area diffuse radiolucent area about second 
about second bicuspid. bicuspid. 

Peiiapical diesase. Class III. Note Periapical disease, Class I, on 

circumscribed radioparent areas, sur- mesial root; Class III, on distal 

rounded by radiopaque line. These root, lower first molar. 
cysts were sterile. 

E F 

Periapical disease, Class II, on Periapical disease. Class I, on left 

cuspid; Class III, on second bi- central; Class II, on right central; 
cuspid. Class III, on right lateral. 

Fig. 7. 


periapical tissues, except a slight thickening in the periapical 
pericementum, or it may present any extent of rarefying 
osteitis. There may or may not be evidence of previous 
attempt at root-canal filling. This condition, in the absence 
of such evidence, is too frequently passed with a glance, 
when a more prolonged study will reveal an absence of the 
apical lamina dura and an indefinitely circumscribed area, to 
a varying degree more radiolucent than the surrounding 
bone. To fall into Class I, however, no matter what the 
degree of periapical disturbance, the area must be circum- 
scribed, with the radiolucent area blending gradually into 
the normal bone. 

In cutting down upon these areas the alveolar plate will 
generally be found to be intact, but behind this a mass of 
soft granulations will be found investing the root apex. This 
class represents the primary results of infection, and the 
affected area is circumscribed, because the vital forces, while 
being slowly overcome by the invading organisms, are, as 
it were, making an orderly retreat. It often happens at this 
stage that proper root-canal treatment so attenuates the 
invading host that the balance of power passes to the tissues, 
and a cure results. 

For the better understanding of the statement just made 
the microscopical picture of primary granuloma must be 
studied (Fig. 8). Under the low power may be seen a fibrous 
capsule surrounding a cellular central portion. Under high 
power the capsule is seen to be composed of dense white 
fibers of connective tissue, with numerous vessels and capil- 
laries. There is a scattering of wandering tissue cells and 
fibroblasts. The central portion is composed of plasma cells, 
fibroblasts, lymphocytes, and leukocytes, lying in an indefi- 
nite stroma of embrvonic connective tissue. Careful exami- 


nation will reveal the capillary loops often lined with a single 
layer of endothelium. It is from these delicate vessels that 
the inflammatory cells probably have their distribution. 
Such a pathological arrangement is strongly indicative of 
nature's effort to wall off the irritant. 

Fig. 8. — Photomicrograph of advanced granuloma, a, degenerative area; 
b, leukocytes and bacteria; c, fibrinous layer; d, granulation tissue; dd, capil- 
lary loop; e, pericementum. 

Class II (Fig. 6, B) : Diffuse Radiolucent Area. — 
This class shows in the film an irregularity of the radiolucent 
area, which may vary from a simple break in limitation to 
an entire loss of form. As in Class I, the limitations of the 
abnormal area are poorly defined, and it is impossible to 
determine the borderline between normal and rarefied bone, 


so gradually does one blend into the other. The irregu- 
larity of general outline is caused by ramifications of 
inflammatory tissue which extend from the central mass 
into the surrounding bone. Wherever this abnormal tissue 
comes in contact with bone or cementum disintegration of 
the hard tissues takes place. The cementum becomes 
roughened and the bone becomes softened. This condition 
represents the absence of the reparative effort exhibited 
in Class I cases, and follows neglect or improper treat- 
ment of the primary infection. While it sometimes happens 
that Class II cases respond to treatment, the destructive 
process has reached so advanced a stage that it is seldom 
that teeth in this condition are restored to health, except 
by root resection. Indeed, the infection in this class of 
cases is rarely eliminated even by extraction unless exten- 
sive curettement is performed. Under the microscope the 
advanced granuloma shows areas of degeneration in the 
central mass, which appear as lumina containing fluid or 
cheesy matter. 

Class III (Fig. 6, C): Circumscribed Radioparent 
Areas. — In this class the film shows an intensely dark cir- 
cumscribed area surrounding the root apex. This dark area is 
outlined by a dense white line, which definitely separates 
radioparent from normal bone. Such a picture is always 
indicative of a dental cyst. In cutting down on these cases a 
definite cyst wall will be found attached to the root-end. By 
careful dissection this may be freed from its bony capsule and 
by resecting the root just below its attachment the whole cyst 
may be removed en masse. The limiting wall of bone, which 
shows in the radiograph as a dense white line, will be found 
to be smooth and hard. If the cyst be opened it will be found 
to contain a straw-colored fluid. Cysts are an expression of 


nature's effort to protect the organism from the baneful 
effects of certain noxious irritants. Microscopically the cyst 
wall will be seen to be formed of connective-tissue fibers 
lined with epithelial cells. In granulomata which develop 
necrotic areas, epithelial strands may often be seen surround- 
ing the necrotic area. Thus certain Class I cases go on to 
cyst formation, while, on the other hand, the frequency with 
which radicular cysts appear as a late sequel to devitalization 
of the pulp from traumatism, suggests the possibility that 
in some instances these growths are not of infectious origin. 
Whether infected or not, cases of completed cyst formation 
as included in Class III are probably never eradicated by 
treatment through the canal. The cyst wall must be entirely 
destroyed or the cyst will reform. 

Fig. 9. — Chronic abscess with fistulse. Note absence of periapical 

A type of periapical disease not mentioned above which is 
frequently encountered is alveolar abscess, either acute or 
chronic, with tendency to fistula formation. This may 
present a radiographic record identical with any of the fore- 
going classes, or in extremely rapid establishment of drainage 
may produce so little periapical destruction as to escape 



detection in the film (Fig. 9.) Where an abscess exists in 
conjunction with Classes I, II, or III of periapical disease, 
it is usually caused by the secondary invasion of Staphylo- 
cocci pyogenes. When acute alveolar abscess does not 
record proliferative tissue changes in the film, it is likely to 
be the result of infection by the Staphylococcus pyogenes, 
the Streptococcus hemolyticus, or both. 

A further important point for study in the radiograph is 
the condition of the root apex, and this is obviously of greater 
prognostic value than the condition of the surrounding bone. 
If the cementum is exposed and roughened it is certain that 
there is no present treatment by which this infected necrotic 
tissue can be restored to life, to say nothing of health. 

Fig. 10. — Lower cells of antrum. 
Trace pericementum about apex of 
lingual root of molar. 

Fig. 11. — The nostrils superimposed 
upon root apices of centrals. 


Anatomical points which seem to cause the most confusion 
are the lower cells of the antrum (Fig. 10), the nostrils (Fig. 
11), and the anterior palatine foramen (Fig. 12) in films of 



the upper teeth, and the mental foramen (Fig. 13) in films 
of the lower. The question of infected areas in these regions 
can be quickly determined by tracing the line of the peri- 

Fig. 12. — A, anterior palatine foramen; B, taken from further to the right 
than A clarifies the diagnosis. 

Fig. 13. — Mental foramen. Note termination of inferior dental cana!. 

cementum around the root apex. If this is intact the dark 
radiolucent area cannot be caused by infection from the 
root-canal. Occasionally it is necessary to get an exposure 
from a different angle to verify the reading (Fig. 12). 




It may as well be acknowledged that there are many 
infected teeth which cannot be saved, but a selection of risks, 
through careful diagnosis, makes a favorable prognosis rea- 
sonably safe in many instances. For the sake of convenience, 
infected teeth which are rarely benefited by treatment 
through the canal may be classified in three groups as follows 
(Fig. 14): 

Group I Group II Group III 

Fig 14. — Types unfavorable for canal medication. I, too much dead 
apical cementum; II, too much dead alveolar cementum (pyorrhea); III, 
canal opening within the antrum. 

Group I. — Teeth having considerable dead apical cemen- 

Group II. — Teeth having considerable dead alveolar 

Group III. — Teeth having their apical opening within the 
maxillary sinus. 

Group I (Fig. 15). — A careful consideration of these three 
groups may have a tendency to prevent many unsuccess- 
ful attempts at tooth treatment. Recalling the classification 
of periapical disease previously referred to, it will be realized 
that most cases of Class II and all cases of Class III have so 
much denuded and therefore dead apical cementum that 



they must be included in Group I. After one has extracted 
a number of such teeth and curetted the periapical bone, or 
better still, has cut down upon them for root-resections, it 
requires considerable faith in the potency of antiseptics to 
believe that this infected field, full of dead and dying tissue, 
with the exposed apical cementum, which can neither be 
sterilized nor insulated, acting as a continuous irritant, can 
ever be restored to health by treatment through the canal. 

Fig. 15. — Group I, too much dead apical cementum. 

Fig. 16. — Group II, too much dead alveolar cementum. 

Group II (Fig. 16). — Teeth having considerable dead 
alveolar cementum are those pulpless teeth which have 
pyorrhea to the extent of pocket formation. In such cases 
there is generally a pathway of drainage established from the 
periapical area to the gingival margin, which can often be 


traced out in the radiograph. Attempts to sterilize such 
teeth invite failure, as constant reinfection will ensue. 

Group III. — Teeth having their apical opening within 
the maxillary sinus when affected with periapical disease are 
of unfavorable prognosis, because in most cases of this char- 
acter it is probable that an infected granulation tissue has 
been substituted about the root apex for the normal lining 
membrane of the antrum, and reinfection is almost certain 
to occur. 

The dental x-ray film is an unreliable guide as to the rela- 
tion of the tooth root and the maxillary sinus. Fortunately 
we have a means of physical diagnosis which is conclusive. 
When the pathfinder is passed through the apical foramen 
in certain upper bicuspids and molars, there is a twinge of 
pain, after which the instrument moves upward without 
resistance or pain. This is an indication that the antrum of 
Highmore has been invaded. 

Artificial perforation of the lateral cementum may usually 
be discovered by the tendency to hemorrhage, and persistent 
seepage. The patient can generally localize the pain as being 
in the gum when an instrument is passed through the perfora- 
tion. Diagnostic wires are often helpful, but if the puncture 
is lingual, or labiobuccal, the radiograph is unreliable. If 
the false opening is accessible, it may at times be filled suc- 
cessfully. Occasionally a puncture near the apex may be so 
capped with gutta-percha that it is not a source of irritation. 
More frequently, however, teeth so mutilated become lame, 
and must be extracted. 


To summarize, then, we are confronted by the prospect 
that the only teeth which offer opportunity for favorable 



prognosis in root-canal treatment are those with Class I 
periapical disease, of limited degree, and those in which the 
periapical conditions are still normal. 

It often happens, after the most exhaustive efforts at diag- 
nosis, that there remains an uncertainty as to the necessity 
for interference with certain teeth. For the most part these 
are teeth with partially filled canals and no evidence of peri- 

Fig. 17. — Coriell's trocar and cannula. 

apical disturbance, or well-filled canals recently treated, 
which still show radiolucent bone areas about the root apex. 
Until some method is advanced of determining when the 
apical foramina have been sealed by a new growth of cemen- 
tum, any tooth with an incomplete canal filling should be 
considered a source of danger, no matter what the periapical 
condition. We must constantly bear in mind that the radio- 


graph is but a record of macroscopical conditions, while 
infection is the result of a microscopical invasion. 

An instrument has recently been devised by Coriell (Fig. 
17), of Baltimore, which is of the greatest value in deciding 
upon the necessity for treatment in these extremely doubtful 
cases. This consists of a trocar drill and cannula, so con- 
structed that it can be used in the right angle hand-piece of 
the dental engine. By means of this instrument a hole may 
be made through the alveolus to the root apex, after which 
the drill may be withdrawn, leaving the cannula in place. 
Through this an uncontaminated culture may be taken, which 
will definitely determine the bacteriological condition of the 
periapical tissues. The operation can be performed w T ith 
local anesthesia in a few minutes, but the utmost aseptic 
precaution is necessary to make the result of value. 



The object of asepsis is to reduce to a minimum the amount 
of infection which may be introduced into the field by an 
operation. Any aseptic technic gives at best only relatively 
sterile results. The most careful surgeon cannot incise the 
skin without some contamination. Fortunately, most of 
the organisms thus introduced are non-pathogenic, and the 
natural resistance of the tissues defends them from the bane- 
ful effects of bacteria, if introduced only in limited amount. 
Natural resistance is dependent upon the elements of the 
blood stream, which is entirely absent from the dentin of a 
pulpless tooth. Thus the difficulty of an aseptic root-canal 
technic is augmented at the start. Add to this the natural 
disinclination of the patient to submit to the inconvenience 
of sterile wrappings for the head and face, as well as his 
average inability to pay for the time thus consumed in many 
sittings, and the difficulty increases. Furthermore, consider 
that the use of rubber gloves robs the dentist of that delicate 
sense of touch so necessary to the proper performance of 
root-canal work, and that even with the greatest care the 
hands will usually have to come into contact with some 
unsterile object, and the achievement of an aseptic operation 
as it is generally understood by surgeons becomes next to 
impossible. Notwithstanding these difficulties, the dentist 
is no more justified in introducing infection by way of the 


root-canal, than the general surgeon is in doing so by way 
of the integument. 

The operative field in root-canal work is the smallest 
known to surgery and this to some extent offsets the danger 
of our somewhat loose technic. Bacteria can infect only the 
object with which they come into actual contact. Therefore 
the necessities of the case only demand that nothing shall 
enter the pulp chamber which may carry contamination. It 
is the belief of the writer that this result may be assured by 
the simple technic which follows. 

Before the canal is opened it is a wise precaution to attempt 
the sterilization of the coronal dentin. I am indebted to 
Grieves for suggesting a 10 per cent, solution of beechwood 
creosote in oil of cloves for this purpose. The clove oil is 
used as a penetrating menstruum to carry the creasote, 
which in 10 per cent, solution is not coagulant, in the dentin. 
Where the pulp chamber has not been opened or where the 
canals are blocked off by previous fillings, formocresol is a 
valuable agent. Either of these drugs must be sealed in for 
three or four days, as it requires that time to sterilize dentin 
by such means. Where discoloration of the tooth is not an 
objection, Howe's silver reduction method may be used and 
the delay avoided. 


After the attempt to sterilize the coronal dentin, the tooth 
should be opened only when blocked off by the rubber dam, 
which should expose as few teeth as are necessary to give an 
unobstructed view. The dam should be adjusted in such a 
manner that there is no possibility of leakage of fluids from 


the mouth. The teeth included should be rubbed dry with 
gauze or cotton to remove the mucus, and the entire field 
then painted with tincture of iodin. After this has dried it 
is washed off with alcohol to lighten the field. The coronal 
cavity may now be opened. 

Where cavities extend below the gingiva, or the crown is 
wanting, it is necessary to prepare the tooth for the reception 
of the rubber dam. This is most conveniently done with the 
manufactured copper bands which are supplied for amalgam 
work. The band should be cut to conformity with the gin- 
gival margin and articulation and be securely cemented to 
place with a good crown-and-bridge cement. For anterior 
roots the band may be cut away labially in such a manner 
that a flat back facing may be ground to fit. By arranging 
the facing so that it does not come into contact with the 
opposing teeth in mastication, and bending the pins together 
to form an arch, it will adhere to the gutta-percha reasonably 
well for two or three days. 

Cotton and dressings used in root-canal work are probably 
the most frequent sources of contamination. To avoid this 
the operator should have available a sufficient number of 
sterilized packages to meet his daily need. The package is 
prepared as follows: a thick towel, large enough to cover 
the operating table is folded evenly to a size about four by 
eight inches. Upon one end of this is laid a small J. & J. 
napkin folded twice upon itself. On the napkin are laid two 
sections of cotton rolls, about two dozen J. & J. absorbent 
points, a number of small cotton balls and at least half a 
dozen smooth broaches wrapped with cotton. Three or four 
of the long Darby absorbent points will also be found useful. 
These dressings are now covered with another folded napkin 
and the towel folded over it. The whole is now securely but 



not tightly wrapped in a piece of unbleached muslin, which is 
pinned to hold it together. As many of these packages as 
may be required are daily made up and sterilized. 

Fig. 18. — Sterilizing room made in closet. Autoclave for goods in packages 
and wet sterilizer for instruments. 


For the sterilization of dressings there is nothing so abso- 
lute as the autoclave or high pressure sterilizer (Fig. 18). 


When subjected to steam under fifteen pounds' pressure for 
twenty minutes positive sterilization is assured. Then by 
subjecting to negative pressure for about ten minutes, the 
packages are rendered almost free from moisture. This is of 
great advantage in preventing rust on the cotton wrapped 
broaches. High-pressure sterilizers are somewhat expensive, 
but the certainty of sterility makes the expenditure worth 
while for any dentist who does much root-canal work. 

Xext in efficiency to the autoclave for this purpose is an 
ordinary gas cooking range. Almost any large vessel may be 
arranged to support a perforated platform on which the dress- 
ings may be subjected to live steam, without actually coming 
into contact with the boiling water. After thirty minutes 
of such treatment, the packages may be placed on a tray and 
put in the oven to be subjected to dry heat for an hour or two. 
Care must be taken to prevent overheating the oven and thus 
burning the dressings. 

The Pentz sterilizer is advocated by many careful root- 
canal workers, and probably is efficient for cotton or gauze 
laid loosely on the tray, but if such a method of sterilization 
were satisfactory for goods in packages, one would expect 
to find it in use in our large hospitals. 

A mouth mirror, two or three pairs of cotton pliers, rubber- 
dam clamp forceps and clamps, a pair of collar pliers, a few 
broach holders and necessary excavators, chisels and burs 
should be placed upon a perforated tray and sterilized by 
boiling for twenty minutes prior to the operatin 

Barbed broaches and smooth broaches for carrying cotton 
dressings may be kept in alcohol. Wide-necked bottles, such 
as the ordinary amalgam bottle, are fitted with corks, into 
the under side of which the broaches are stuck in such a 
manner that when the cork is in the bottle the instruments 



will be immersed in the alcohol. The addition of one part of 
oil of sweet almonds to nine parts of alcohol, will prevent 
rusting, no matter how long the instruments are thus kept. 

Having made the foregoing preparations, we are now ready 
to set the table for the operation (Fig. 19). The ordinary 
bracket table is so unsteady that greater safety is assured by 
using a glass surgical table, so placed that it is within easy 

Fig. 19. — Table set for aseptic root-canal technic. 

reach of the operator and assistant. To the back of the table 
may be placed the medicaments likely to be of use, such as 
iodin, alcohol, canal antiseptics, peroxid of hydrogen, 30 per 
cent, sulphuric acid, xylol, temporary stopping, etc. At one 
end a Bunsen burner should be arranged, as it is frequently 
necessary to flame the cotton pliers or collar pliers. An open 
receptacle, such as a hair-receiver, for waste material should 
also be provided. 


The table top is wiped off with alcohol and covered with a 
sterile towel from one of the packages. The package should 
be opened in such a manner that the fingers do not contami- 
nate its contents. The towel is then removed with two pairs 
of flamed forceps and spread upon the table. The package 
of dressings is placed on the end of the towel, being sure that 
they are completely covered by one of the folded napkins. 
On the extreme back of the towel are now set the bottles 
containing the broaches in alcohol. The corks are removed 
and reversed and set upon the towel just in front of their 
respective bottles. The long-handled broaches are then 
placed in the bottles to sterilize. 


A very good assortment of root-canal instruments is as 
follows : 

1st bottle — Four pathfinders of assorted sizes. 

2d bottle — Four apexographers of assorted sizes. 

3d bottle — Two XXX and two XX Rhein root-picks. 

4th bottle — Two X and two fine Rhein root-picks. 

The handles of these instruments should be so marked with 
a file that the size can be determined at a glance. 

5th bottle — Two No. 1 and two No. 2 Kerr root-canal files. 

6th bottle — Two No. 3 and two No. 4 Kerr root-canal files. 

7th bottle — Two No. 5 and two No. 6 Kerr root-canal files. 

These instruments have had the irritating tendency to 
loosen in the handles, but those now being manufactured 
are improved in this respect. 

8th bottle — Set of Crane root-canal openers. 

9th bottle — Assorted sizes Rhein canal enlargers. 

The handles of all these instruments should lean to the side 


of the bottle next the operator. When one is used it is 
returned to the bottle leaning in the opposite direction, thus 
resting the instrument. 

Short handled instruments should be placed in a covered 
Petri dish well filled with alcohol. A half dozen of the three 
smaller sizes of Kerr root-files, a couple of small Young 
broaches and a few fine barbed broaches make a satisfactory 
assortment. When a short-handled instrument is used the 
fingers should be thoroughly immersed as the instrument is 
picked out of the alcohol. As soon as they become dry they 
should be immersed again, otherwise contamination of the 
field may be expected. 

The assistant may set the table while the operator is wash- 
ing his hands, adjusting the rubber dam and removing the 
temporary filling. By this time the instruments in the alcohol 
will be sterile and the operation may proceed. 

The cotton rolls in the sterile packages are for use in the 
event of the inadvertent puncture or tearing of the rubber 
dam while the coronal cavity is open. By stretching the dam 
a trifle, one of these rolls held in forceps may be made to 
plug the opening while the coronal cavity is sealed, after 
which a new piece of dam should be adjusted before con- 
tinuing the operation. The rolls are also useful for making 
sterile cotton swabs for the canal in the following manner: 
From a cork containing fine barbed broaches which have been 
somewhat worn down by use, select one of proper size, 
sticking the barbed end into the cut end of the roll and giving 
it a couple of turns. Upon withdrawal the cotton fibers will 
be wrapped around the instrument in such a manner that they 
will not slip from it in swabbing out the canal. Still another 
use for the rolls is absorbing solutions used to irrigate the 


For use in quickly sealing the cavity in the event that it is 
necessary to change the rubber dam a number of small cotton 
pellets are dropped into melted paraffin and allowed to boil 
for twenty minutes. They are then individually removed 
with sterile cotton pliers and laid on a sterile towel to cool. 
When they have hardened they are placed in a screw-top 
bottle and kept in a convenient place on the table. When 
needed it is only necessary to take one in the cotton pliers 
and hold it an instant in the Bunsen flame, when it may be 
pressed into the cavity effectively sealing it while the dam is 
being changed. 

Gutta-percha points should be prepared for use as follows : 
Dip in iodin and place on sterile glass slab to dry, wash off 
with alcohol, and then place in an alcohol bath in a suitable 
covered container. 

. 4 



It has been pointed out that before entering the pulp 
chamber an attempt should be made to sterilize the coronal 
dentin. Thereafter the rubber dam should be applied and 
the coronal cavity so shaped that free direct access may be 
had to each canal in a line with its long axis. It is unfortu- 
nate that this often means extensive destruction of sound 
tooth substance, but even if the whole crown must be sacri- 
ficed the procedure is justified. The coronal opening corre- 
sponds to the primary incision in any other surgical operation, 
and as the object here is the safety of the root, as much of the 
crown should be sacrificed as may be necessary to prevent 
failure (Fig. 20). Wherever possible, the natural walls of the 
pulp chamber should be preserved, as these will guide the 
broach naturally into the canals. The best method is to 
enlarge the cavity of access until the roof of the pulp chamber 
consists of only a thin layer of dentin, and then remove this 
with chisels and hoes (Fig. 21). 

In bicuspids and molars it is always necessary to enlarge 
mesial cavities well into the occlusal surface, and frequently, 
when the decayed or filled cavity is distal, it will be expedient 
to cut somewhat into the mesiobuccal surface as well. Those 
familiar with the Black system of cavity preparation will 
understand how to shape these cavities so as not to weaken 



the tooth. The cutting is best done with a round or inverted 
cone bur, care being used to prevent its plunging into the 
pulp chamber. No overhanging walls should be left at any 



Fig. 20. — Incorrect technic. 

point. In incisors and cuspids the lingual wall must generally 
be cut away, no matter where the cavity of decay exists. 
Enough dentin should be removed toward the incisal surface 
to completely expose the horns of the pulp. In either class 
of teeth, should the broach bind on any of the cavity walls, 



Fig. 21. — Correct technic. 

when inserted in the canal, more cutting should be done in 
that direction until the broach is absolutely free. 
The conscientious operator will have made a careful study 


of dental anatomy and be aware of the normal number and 
location of the canals in each type of tooth. Variations from 
the typical are to be expected and looked for. There are often 
two distal canals in the lower first molar. The mesiobuccal 
root of the upper first molar sometimes contains two canals. 
There are not a few lower second molars with only one large 
canal and upper second molars with one or two canals only. 
Lower bicuspids are found with two canals and upper second 
bicuspids frequently have two. I have encountered three 
lower bicuspids with two well-defined canals and a few upper 
cuspids with a second canal running into a rudimentary root. 
The lower third molars may have from one to four canals and 
the upper as many as seven. The possible presence of such 
abnormalities should serve to keep the operator always on 
guard, for no matter how well the canals which are found are 
managed, an untreated canal will entirely vitiate the result. 
On the other hand, if a canal cannot be found it will do no 
good to form an artificial one, and this attempt generally 
results in puncture of the root. 

When difficulty arises in the search for the canals, it is 
generally because the floor of the pulp chamber has been 
mutilated. Other factors tending to impede progress are 
insufficient access, previous canal fillings or chips of dentin 
in the canal orifice. If the radiograph indicates that the 
canals are blocked by fillings, some solvent should be used. 
For gutta-percha the pulp chamber should be flooded with 
xylol, which in a few minutes will so soften this material that 
the finder will slip into the canal. If the obstruction is of 
cement or a proprietary root-filling, the canals may be located 
by painting the floor of the pulp chamber with iodin. When 
this is washed out with alcohol the root-filling will retain the 


If the orifice of the canal is filled with chips of dentin, pulp 
stones or hardened pulp tissue, a small piece of sodium- 
potassium should be placed in the pulp chamber and spread 
evenly over the floor. A broken root pick sharpened to a 
point is then used to systematically sweep this surface until 
it becomes engaged in the orifice of the canal. When this 
fails, occasionally a 50 per cent, sulphuric acid followed by 
bicarbonate of soda will succeed. The temptation to use a 
bur in an attempt to uncover the canal in these cases is some- 
times almost irresistible, but to do so is sure to complicate 
matters still further. 


Having located the canals by whatever means, the work 
in the canal proper is begun by exploring to its apical extrem- 
ity. Upon the complete accomplishment of this task the 
success of the subsequent work depends. There are certain 
canals which cannot be so explored by any technic at present 
available, but the proportion of such is much less than it 
would seem to the inexperienced. 

A fine, smooth broach of piano wire is the only instrument 
which can be depended upon to do this part of the work with 
safety. The Rhein root pick, the Twentieth Century path- 
finder and the Kerr root probe are all instruments designed 
for this purpose. The Kerr set contains the finest instrument 
of this type, not much thicker than a hair, which is often very 
useful, but these probes are made of blued steel, which makes 
them difficult to see in operation. The pathfinder is a long 
delicate instrument with which good work may be accom- 
plished, but the flexibility of the long shank confuses the sense 
of touch to some degree. 



Crane Canal Openers. — It is not unusual to encounter canals 
so plugged with organic debris or other obstruction, that 
when pressure is made upon the smooth broach the point 
buckles, thus retarding its progress. For the purpose of 
overcoming this I have recently had made by the Donaldson 
Broach Company a set of canal openers. This consists of 
four instruments of the root-pick type, the modification being 
that the working points are of varying lengths, thus increasing 

Fig. 22. — Crane opener for difficult canals. 

the relative length of the shanks. The No. 1 opener has a 
fine point one-eighth of an inch long; No. 2 is one-fourth inch; 
No. 3 is three-eighths and No. 4 one-half. If these instru- 
ments are used successively, beginning with the shortest, they 
will enable the operator to explore difficult canals without 
the buckling of the instrument interfering with the sense 
of touch. After the longest opener has been buried to its 
shank in the canal, the root-pick will usually complete the 


For routine work the Rhein picks, which come in four 
sizes, are admirable. 

Selecting the smallest size the attempt is made to follow 
the canal to the apical opening by a series of pushing and 
picking motions (Fig. 25, A). If the progress of the broach 
is stopped a comma-like turn given to the extreme point of 
the instrument will frequently allow it to proceed. If this 
fails, sometimes a slight quarter-turn twisting motion given 
just at the impact of the picking motion will cause it to pass 
the obstruction. Xo great force should be used, however, 
and where purely mechanical exploration fails chemical aid 
is indicated. This should not be undertaken blindly, but the 
cause of the obstruction should be ascertained if possible. 


Acids should be used for inorganic blockade, alkalies for 
organic, and suitable solvents for previous canal fillings. 

The principal acids used for this purpose are 30 per cent, 
sulphuric, phenolsulphonic and hydrochloric. The life-work 
of Callahan with the sulphuric acid gives it preeminence 
and, where indicated, it renders a useful service. An appli- 
cator may be made of fine iridioplatinum wire, filed to a taper 
point and somewhat roughened with a coarse file. A satu- 
rated solution of bicarbonate of soda in sterile water should 
subsequently be used for the double purpose of neutralizing 
any free acid remaining, and forcing out the debris by the 
bubbling which ensues. 



The principal alkalies are sodium-potassium, sodium- 
dioxid and sodium-hydroxid. Of this group the sodium- 
potassium is easiest to handle and meets all the requirements. 
The best form is Schreier's paste, which was obtainable in 
Germany before the war, but the S. S. White Company 
makes a preparation which is quite satisfactory. It comes 
in a small glass tube which can be kept sealed with wax when 
not in use. In use the tube is nicked with a knife-edged file 
just above the point where the silver color shows the alloy 
unchanged, and the tube broken off at this point. A white 
substance forms at the top of the tube from contact with air 
and this should be discarded. The point only of the pick is 
dipped into the sodium-potassium and it should merely be 
painted with the alloy; that is, no lumps should adhere to 
the instrument. It may be more impressive to say, "Use 
sodium-potassium only in homeopathic doses." When this 
substance comes into contact with moist organic material 
there is a miniature explosion, attended by flame and smoke, 
caused by the rapid oxidation. In this reaction some of the 
organic material is actually consumed and some is saponified. 
The use of sodium-potassium in the canal is only occasionally 
attended by explosion, hence the saponified tissue must be 
washed out of the canal, for which purpose alcohol is an 
efficient medium. Repeated applications will eventually 
remove any organic blockade. 

As previously stated, alkalies are indicated for organic 
obstructions, but where the closure is caused by a calcific 
nodule or a constriction of the canal walls, sodium-potassium 
will more quickly effect a passage than acids. This is because 
it destroys the organic cementing stroma of the dentin as well 


as the organic matter in the dentinal tubuli, leaving the 
inorganic portion in such form that it is readily pulverized 
by the broach. Thus it is the best chemical aid for routine 
use in removing natural obstructions. 

Gutta-percha is the most frequently encountered artificial 
obstruction. For dissolving this, chloroform, eucalyptol or 
xylol may be used. The latter possesses many advantages 
over the other two and in a few minutes will so soften the 
hardest gutta-percha that the pick will pass through it. 

Obstructions caused by proprietary root pastes will be 
slowly softened by sulphuric acid, in the rare event that they 
are hard enough to offer any resistance to the passage of the 
pick. Gold or cement must be painstakingly picked out. 
A stiff, pointed instrument made of a broken root pick 
is most useful for this purpose. 

Broken instruments offer the greatest difficulty of any 
canal obstruction. It may here be pointed out, however, 
that this does not apply to smooth instruments broken off 
in the picking and pushing motion. If these are simply 
ignored for the time being and the picking and pushing 
resumed with a new instrument, the broken portion will soon 
ride out of the canal, but where an instrument is broken 
while being screwed into the canal further exploration is often 
impossible. By repeated use of sodium-potassium on a root 
pick, it is sometimes possible to make a pathway alongside 
of the obstruction, and then a twist broach may be passed 
into this and twisted around and around to the right, without 
permitting it to advance into the opening. When this does 
not work it is feasible occasionally to continue the picking 
alongside of the broken instrument and reenter the canal 
at a point apical to it. When the broken piece projects peri- 
apically, extraction or root-resection is indicated. 




After the canal has been explored as far as possible by the 
foregoing method, successive sizes of root picks, carrying 
smallest quantities of sodium-potassium should be used, 
passing them to the farthest point of exploration and then 
pressing around the side walls of the canal (Fig. 26, A). In 
this way the opening may be made large enough for the 
insertion of a diagnostic wire (Fig. 23). For this purpose 
there is nothing better than a strand of ordinary braided 

Fig. 23. — Diagnostic wires. 

picture wire. Enough of this to last a life-time can be bought 
for five or ten cents, and it has all the qualities necessary for 
this use. Where the caliber of the canal permits, the diag- 
nostic wire may be wrapped with cotton fibers and saturated 
with any medicinal agent indicated. The end of the wire 
which is to remain in the pulp chamber should be given a 
turn around the beaks of the cotton pliers so that it may 
readily be grasped for withdrawal. 

After the insertion of the diagnostic wire a radiograph will 
indicate the extent to which the canal has been explored, 
and will be suggestive of subsequent procedure. If a portion 


of the canal is unexplored, where this is straight a stiff pick 
or fine root file may be used with considerable force to com- 
plete the opening. If the canal is curved, the smooth broach 
should be curved to approximately the same degree and the 
gentle pushing and picking motions resumed, with the aid 
of the indicated chemical. 

A common error in dealing with curved roots is to enlarge 
the canal with burs or reamers in the direction of the long 
axis of the unexplored portion. This possibly might be tried 
as a last resource, but to mutilate the canal with any instru- 




Fig. 24. — Common errors. 

ment prior to exploring to the apical foramen is to invite 
almost certain failure to accomplish the desired result. 

The attempt to use a broach of any kind as a gimlet or to 
use any instrument revolved by the engine will often result 
in forcing debris ahead until the canal is hopelessly occluded. 
The formation of an offset or shoulder, which will deflect 
the broach when again used, the puncture of the root, or the 
fracture of the instrument within the canal, are other potent 
probabilities of such indiscretion (Fig. 24). 

When the use of the canal openers fails to open the canal 
the use of the finest Kerr root file or Young broach in quarter 


turns is sometimes indicated, but the frequent withdrawal 
and cleansing of the instrument must not be neglected. 

If the canal cannot be explored to the end, it should be 
enlarged as far as possible, and the unfilled portion of the 
root subsequently resected. 

Where previous partial root-canal fillings are found they 
should be completely removed prior to the attempt to explore 
the remainder of the canal. Most frequently an offset will 
have been formed at the extremity of the filling, by the pre- 
vious operation (Fig. 25). It is quite difficult in such event 
to find the continuation of the canal proper. This is best 

Fig. 25. — Offset clearly shown in distal canal of first molar. 

done by giving the comma-shaped curve to the end of the 
root pick. Then by picking away, revolving the instrument 
just a little with each pick, the point will often slip past the 
shoulder and continue on its apical journey. Xo attempt 
should be made to eliminate the shoulder until after the 
extremity of the canal has been opened by the smooth- 
broach sodium-potassium method, so as to admit the free 
insertion of the largest size Rhein pick. Then by adherence 
to the technic about to be described for enlarging and shaping 
the canal, the shoulder may be so rounded off that it will 
offer no interference in the placing of the filling. 




Having reached the periapical tissue by some means, the 
next step is to enlarge and reshape the canal, thereby inci- 
dentally removing most of its original content, especially if 
judicious use is made of sodium-potassium. The object is to 
make the canal of such caliber that a sufficiently firm gutta- 
percha point may be employed in filling it, and to shape it 
to a conical form, so that when pressure is brought to bear 




Fig. 26. — Correct technic. 

on the gutta-percha cone at the canal orifice, it will be packed 
simultaneously against the side walls and the apex of the 
canal. Correct cavity preparation is as essential to good canal 
filling as to coronal filling . > 

The desired result* is safely- obtained' by 1 the -use of a 
graduated series of Kerr root-canal files. " ' ^Yobrig* hroaches, 
Donaldson barbed broaches, or 'Twentieth 'Cetitury rat-tail 
files may be employed, but the Kerr file offers 1 the most 
advantages. - •" ; 



The instrument first used must be of the smallest size and 
of no larger gage than the last smooth broach used in the 
exploring operation. With gentle pressure this is pushed to 
the end of the canal and withdrawn with lateral pressure. 
This is repeated again and again, always making the broach 
scrape toward the crown, never toward the apex, curetting 
systematically all around the canal (Fig. 26, B). The file 
should never be twisted into the canal, but its insertion 
may be aided by minute quantities of sodium-potassium 
(Fig. 27, A.) 


broach too 



Fig. 27. — Incorrect technic. 

The next size larger file is now substituted, in the same 
manner pushing it to the apical opening and shaving the 
walls of the canal only upon withdrawal. By using succes- 
sively larger sizes of files and repeating the technic just 
described, the canal, even if curved or twisted, can be 
enlarged to any size and wiJI be formed to a conical shape. 

The enjargemerit of the canal only upon the withdrawal 
of the instrument tends to carry most of the debris into the 
pulp chamber. This may be blown out from time to time 


with the chip blower, but while this is being done the broach 
should always remain in the canal to block the apical opening. 
The toilet of the canal is accomplished with hydrogen- 
peroxid, to which bichloride of mercury may be added in 
proportion of 1 to 500, if desired. A drop is placed at the 
canal orifice and is gently worked into the canal with a fine 
absorbent point. Care must be exercised to prevent blocking 
the canal with the cotton, as this would cause effervescence 
to take place apically. 


The management of the apical opening depends upon the 
type of filling to be inserted. Where periapical conditions 
are still normal and it is desired to confine the filling entirely 
within the canal, the apical opening should not be enlarged, 
but should remain as nearly normal as possible. Where 
periapical destruction has occurred and it is desired to project 
the filling material to form a cap for the root apex, the apical 
opening should be more or less enlarged depending upon the 
degree of disorganization. The Twentieth Century apexog- 
rapher, or apex curette is an instrument ideally constructed 
for this delicate task. The finest size will readily pass through 
the apical foramen of the average tooth which has undergone 
the foregoing treatment, but will catch just a trifle upon 
withdrawal, thus enlarging the lumen and drawing the 
debris into the canal (Fig. 26, 0). Where the natural opening 
is too small to permit the free passage of the smallest instru- 
ment, it may be worked through by alternately giving quarter 
turns and withdrawing the instrument. There are several 
sizes of apexographers, and by using them successively the 



apical opening can be safely enlarged to meet the require- 
ments of the case. 

In curved or twisted canals, the smooth broach used in 
exploring will usually come out of the canal so bent to 
conformity that it may be readily reinserted. A broach so 
shaped should be laid aside as a pattern by which to bend 

A B 

Fig. 28. — The result of one hour's work by technic herein described. 
A, case as it presented; B, diagnostic wire in position. 

each instrument subsequently used in the canal (Fig. 28). 
Sometimes it is even expedient to bend the gutta-percha 
point to conform to this pattern. 

After enlarging the apical opening the canal is again washed 
out with hydrogen-peroxid and is then ready for the process 
of disinfection. 


The upward progress of dentistry has been marked from 
the beginning by a tendency to perfect the purely mechanical 
and compromise with the therapeutical. In the struggle to 
reconstruct our root-canal technic to meet the requirements 
of advanced medical thought history has repeated itself. 
"While many operators are capable of opening and filling 
root-canals in a satisfactory manner, it is doubtful if any 
thoughtful dentist can approach root-canal work with the 
same degree of assurance that he would undertake the making 
of an inlay or a crown. The cause of this hesitancy lies in 
the uncertainty of accomplishing the eradication of the infec- 
tion. Until some scientifically correct method of making 
cultures in root-canal work is determined, the sealing of the 
canal will be fraught with the dangerous possibility that the 
infection still persists. While awaiting this discovery a care- 
ful study should be made of the possibilities and limitations 
of sterilization in periapical disease. Such a study requires a 
visualization of the pathological condition of the tooth and 
its investing tissues. 

In a typical case of periapical infection the tooth is pulpless, 
and the canal contains more or less infected organic matter. 
The contents of the dentinal tubuli have undergone a change 
due to the action of the invading bacteria. This degenera- 
tion may be confined to the immediate region of the canal, 


but except in cases of short standing, it extends well toward, 
if not quite to, the dentocemental junction. Wherever this 
change has occurred the dentin is not only dead, but infected. 
Externally the cementum covering the root apex may be 
necrotic to a greater or less extent and saturated with the 
products of infection. 

Of the investing tissues the attachment of the apical fibers 
of the pericementum has been destroyed, and this destruc- 
tion often extends to the fibers of the oblique groups as well. 
To the extent to which this detachment has deprived the 
cementum of its blood nutrition, an irreversible change has 
occurred in the hard tissues. 

The cancellous bone surrounding this necrotic portion of 
the root has undergone a rarefying osteitis, in which process 
an infected granulation tissue has been substituted for the 
normal bone. The surface of this proliferating tissue which 
approximates the necrotic tissue has a tendency to undergo 
an indolent liquefaction, and in advanced granulomata this 
metamorphosis also takes place where the soft tissue comes 
into contact with the bone. In either instance the hard tissue 
deteriorates. The cementum becomes roughened and the 
bone becomes softened. 

If the foregoing clinical picture is in accordance with the 
facts, it must be acknowledged that, in cases of periapical 
infection, infection exists in the following sites: (1) The 
canal and canal walls; (2) the dentinal tubuli; (3) the apical 
cementum; (4) the granulation tissue investing the apex; 
(5) often in the bone adjacent to the granuloma. Further, 
it must be recognized that each of these areas is dependent 
upon or contributory to the others, hence it cannot be 
assumed that sterilization is complete until the infection in 
each of these sites has been eliminated. 


The difficulty of thoroughly sterilizing these interdependent 
seats of infection is augmented by the fact that both living 
and dead tissues are involved. The researches of Carrel, 
ratifying and amplifying the findings of many previous inves- 
tigators, are decidedly convincing in the conclusion that 
infections in living tissue can seldom be overcome by satu- 
rating them with drugs strong enough to destroy the tissue 
cells. In dead tissue, on the other hand, dependence must 
be placed upon the germicidal effect of poisons brought into 
actual contact with the invading organisms. It would appear, 
then, that the attempt to sterilize both living and dead tissue 
by the same agency is irrational and impracticable. 

With these facts in mind let us proceed to a consideration 
of the most widely accepted methods of tooth treatment in 
an effort to determine why they are successful and wherein 
they fail. 


For the purpose of disinfecting dentin dependence has 
always been placed on the action of drugs. At first empir- 
ically, and latterly more scientifically, the dentist has sought 
to accomplish with disinfectants in the teeth what the general 
surgeon has also attempted in other tissues. The trend of 
modern surgery, however, is to place more and more depend- 
ence upon the vital resistance of the tissues. By control of 
the inflammatory reaction, infection is inhibited and repair 
ensues. In dead tissue, on the contrary, there is no inflam- 
matory reaction to control, and sterilization can only be 
effected by the direct action of bacterial poisons. The 
greatest drawback to success in this necessity is the difficulty 
of confining the treatment to the canal, for agents which 


might be depended upon to sterilize the canal and dentin are 
generally so inimical to the vitality of the periapical tissues 
that we have been repeatedly warned by careful investigators 
to discontinue the use of all irritating drugs. Other investi- 
gators, equally careful, claim that only by the use of such 
drugs can dentin be sterilized, and that periapical damage is 
due to faulty technic, rather than the inherent property of 
the medicament. 

Light may be thrown upon this controversy by a considera- 
tion of the theory that, in destroying bacteria by the use of 
drugs, there is most probably a definite chemical reaction by 
which the characteristics of both bacterium and drug are lost 
and inert substances produced. 

As in any chemical reaction an excess of either of the 
factors will remain unchanged with all its original character- 
istics. In the nice reactions which Buckley has worked out 
to show the rationale of formocresol medication this pos- 
sibility is not accentuated, although he is insistent upon the 
use of minimum quantities of this drug. It would be fatuous 
to deny that many teeth have been restored to health and 
usefulness by the aid of this and other powerful drugs, but 
this result has been obtained by a chance happening upon 
just the proper amount of the remedy for the particular case; 
where used in excess nothing but harm has resulted. 


The treatment of root-canals by a silver reduction method, 
as suggested by Howe, is a valuable therapeutic agency in 
many cases. The chemical reaction which occurs, however, 
is subject to the possibility of excess of either reagent. Howe 
therefore advises that after the mixture of the two solutions 


in the canal is complete, the excess should be absorbed with 
cotton points, and the canal again flooded with the silver 
solution to take care of any excess of formalin remaining. 
The dense black stain which inevitably follows its use tends 
to limit the employment of this treatment to certain posterior 
teeth. This statement is made in full knowledge of the 
methods which have been devised to protect the coronal 
dentin from the stain, and at the same time also prevent 
its sterilization. If eugenol or any other drug can be depended 
upon to sterilize the coronal dentin it would seem that it 
might be equally efficacious in the dentin of the root. 

Silver reduction by means of eugenol has been advocated 
by some, and it oifers the advantage of less irritation in event 
of its passage through the apical foramen. 

Many teeth have been treated in past years with silver 
nitrate, and the writer has seen a number of most favorable 
results. Whether the silver reduction methods are in any 
way superior to the straight silver nitrate is an open question. 


A group of substances studied by Dakin and elaborated 
by others has made possible a new technic in the surgery of 
suppurating wounds. The attempt to make use of these 
drugs in root-canal therapy has not been an astonishing 
success, for the reason principally that, when the solution 
comes into contact with the secretions from the periapical 
region or the fluid debris of the dentinal tubuli, it is so diluted 
that in fifteen or twenty minutes no active substance remains. 
Concentration can only be maintained by constant renewal 
of the agent. By mixture with stearates or neutral oil this 


tendency to dilution is somewhat overcome, and this is one 
reason for the more favorable results with dichloramin-T. 

Dichloramin-T should be used not stronger than 5 per cent. 
For dressing the canal with this medicament it is better to 
use the prepared cotton points thus avoiding the use of 
metallic instruments. It should be securely sealed in the 
canal and be renewed at frequent intervals. It is probable 
that the best results would be obtained by changing the 
dressings three or four times daily for a couple of days. 


Happily the organisms with which we have to deal in root- 
canal work are not highly resistant. If a mild germicide can 
be brought into actual contact with the bacteria in proper 
concentration for a sufficient period of time, all that can be 
expected in the control of the infection will be accomplished. 
To achieve this end it is necessary to first deplete the tubuli 
of the organic content as thoroughly as possible. If sodium- 
potassium alloy has not already been used, it should be used 
now for this object, the debris scraped from the canal walls 
with Donaldson broaches, and the canal washed out with 
alcohol. With a Sauser irrigator the canal is then gently 
flooded with hydrogen peroxid. This is dried out with cotton 
points and the canal walls painted with 30 per cent, sulphuric 
acid, worked with a roughened platinum broach. This in 
turn is absorbed with cotton points. This treatment tends to 
deplete the dentinal tubuli of their organic content, and goes 
far toward sterilizing the dentin. Possibly in many cases this 
can be completed by dressing the canal with antiseptic oils. 
According to Black the oils possess the property of soaking 
into dentin and displacing its watery content. ^Yhether 


such weak germicides as 10 per cent, solution of beechwood 
creasote in oil of cloves, Black's "1-2-3," or apinol retain 
their potency when they thus saturate the deeper portions of 
the dentin is a subject for further investigation. Clinically 
they seem to answer the requirements, and at least their use 
is not attended with danger to the periapical tissues. 

Dead dentin, like other necrotic tissues, when retained in 
situ must be considered a foreign body. It can be made 
innocuous only by sterilization and the obliteration of the 

The sterilization of the periapical region presents an 
entirely different problem. For this purpose formaldehyd 
gas released from various solutions, phenol, and other caus- 
tics, have proved too treacherous to be longer depended upon 
for routine practice, and non-coagulant drugs have appar- 
ently little effect on granulomatous tissue. 


There has been much discussion of late of so-called "ioniza- 
tion," fostered assiduously by the manufacturers of switch- 
boards to be used for this purpose. Owing to lack of a proper 
conception of electrochemistry and electrobiology much 
confusion has resulted from the spread of questionable 
theories. Notwithstanding this, the clinical results of electro- 
lytic medication are so encouraging that it is being advocated 
as the best present means of treating periapical granuloma. 
^Yhether the dentin is sterilized to any considerable depth 
by this agency is open to serious doubt. In order to under- 
stand the rationale of this method of treatment certain 
chemical and electrical phenomena must be studied. 

It will be recalled as one of the early lessons in chemistry 


that certain elements are classed as positive and the others 
as negative. In the union of the elements to form compounds 
the negative unites with the positive. Thus when the chlorin 
atom, which is negative, unites with the sodium atom, which 
is positive, the result is a molecule of sodium chlorid, which 
is neutral; that is equally positive and negative. It is now 
accepted that the attraction which holds atoms together to 
form molecules is electrical, and is accomplished by the 
transfer of one or more electrons from the positive to the 
negative element. These electrons may be expressed as the 
bands which bind the elements into compounds. 

When a substance such as sodium chloride enters into 
solution there is a dissociation or loosening of the attach- 
ment between the positive and negative atoms, by which 
they have more independent freedom of movement than 
when combined in sodium chloride in the solid state. A 
compound decomposable by the electric current is called an 
electrolyte. When an electrolyte is dissolved in water the 
atoms which form the molecule become dissociated to an 
extent which permits their orderly movement with the 
electric current when it is passed through the solution. 

This movement may be more easily understood by a com- 
parison of the "all hands around" of the old quadrille. The 
dancers on the ballroom floor represent the electrolyte in 
solution. The men represent positive atoms and the ladies 
negative atoms. Each man (or positive atom) faces his 
partner (or negative atom) and gives her his hand (or elec- 
tron), and thus the molecule is formed. Xow the music 
starts (corresponding to the making of the electric current), 
and the man passes his partner and gives his hand to the next 
lady, at the same time letting go the hand of his partner. 
Thus a new molecule is formed and this change of partners 


continues until the music (or electric current) ceases. The 
ladies (or negative atoms) are always traveling in one direc- 
tion and the men (or positive atoms) are always traveling 
in the other. To more nearly simulate the movement of ions, 
we must conceive of the "all hands around" as taking place 
in a straight line rather than in the customary circle. Thus, 
when the man (or positive atom) reaches the end of the line 
he will find no partner and will be set free, and the same holds 
true of the lady (or negative atom), so that men (or positive 
atoms) are made free at one end of the line, while ladies (or 
negative atoms) are released at the other. These traveling 
atoms are called ions. When an electrolyte enters into solu- 
tion, so that the attachment of the electrons is sufficiently 
loosened to render its constituent ions capable of thus 
traveling with the electric current, it is said to be ionized. 

Ions are electronegative or electropositive. For general 
purposes it will be sufficient to remember that the metals 
form positive ions, while the halogens and acidic radicals 
form negative ions, but it must not be assumed that all com- 
pounds can be ionized. The electronegative ions are con- 
ducted against the current and flow toward the positive pole, 
thus constituting what is known as the negative current. 
The positive ions conduct the positive current and flow 
toward the negative pole. With the foregoing comment 
as a basis we may now comprehend the clinical application 
of electrolytic medication. 

The root-canal must have been opened and the apical 
foramen enlarged. The rubber dam is adjusted and all 
aseptic precautions observed. The canal is now flooded 
with an electrolyte, that is to say, a watery solution of the 
chemical from which the ions are to be derived. 

If treatment with metallic ions is desired, the positive 


electrode must be placed in the electrolyte and vice versa. 
This is done by means of a needle, which fits into the root- 
canal, held in an insulated terminal on the desired pole of 
the battery. The opposite electrode must now be brought 
into close contact with the skin or mucous membrane of the 
patient. The usual method is to attach or hold it on the 
cheek, adjacent to the tooth. The current is now turned 
on and, by manipulation of the controllers, is cautiously 
passed through the tissues and gradually increased in strength 
until the point of tolerance is reached. This will usually be 
around two milliamperes. Care must be exercised that the 
current is not short-circuited by contact of the needle elec- 
trode with adjacent teeth, metal fillings, or moisture leaking 
through the rubber dam. Multirooted teeth may have all 
roots treated simultaneously by passing a separate needle 
into each canal and twisting or clamping them together. In 
this event the amount of current which will pass through the 
various apical openings will differ, and for this reason it is 
better practice to treat each root separately. 

If the indicator on the milliamperemeter vibrates with 
coincident painful shocks, it is an indication that somewhere 
along the path of the current there is a loose connection which 
should be looked for in the switchboard or terminals, between 
the electrolyte in the canal and the periapical fluids, or 
between the indifferent electrode and the tissues. Enough 
of the electrolyte should be added from time to time to com- 
pensate for evaporation. When the treatment is completed 
the current should be very gradually reduced to zero and then 
turned off. The most disagreeable shock is caused by the 
making and breaking of the current, hence the electrodes 
should only be applied or removed when the current is turned 
off at the switch. After removal of the electrodes any excess 


of electrolyte should be absorbed from the canal with sterile 
cotton points before dressing and sealing the tooth. 

It is probable that electrolysis only carries the ions of the 
electrolyte a short distance into the periapical tissues, for 
the current upon reaching the multiplicity of ions contained 
in the body fluids is given up to them. Thus if ions of zinc 
are carrying the current through the apical opening, they 
will shortly transfer it to sodium ions or calcium ions or other 
electropositive ions already existing in the tissue juices, 
much the same as the baton is transferred from one set of 
runners to another in a relay race. It is by such transfer- 
ence that the electric current passes through the body from 
one electrode to the other. 

Considering this phenomenon it is doubtful, as has just 
been stated, if ions from the electrolyte are deposited to any 
appreciable distance beyond the apical end of the root by 
electrolytic medication. This does not express the limit of 
their distribution, however, for provided precipitation does 
not occur, diffusion begins as soon as the ions are introduced 
into the tissues, and continues actively for upward of twenty- 
four hours. The maximum beneficial effect, if any, produced 
by the ions, is therefore not immediately upon their intro- 
duction, but after diffusion has ensued. 

The two leading American dental writers on electrolytic 
medication, Fette and Prinz, are at variance in their selection 
of an electrolyte. The former, adhering to the technic of 
Sturridge, advises the use of zinc chloride with a needle of 
zinc as the positive electrode; the latter, the use of sodium 
chloride with a platinum needle on the positive pole. Sur- 
prising as it may seem, both claim the same efficient results. 
To avoid confusion let us examine each of these methods 
separately, and see what takes place. 


Fette's Technic of Ionization. — When Fette's technic is used, 
as soon as the current begins to flow zinc ions pass through 
the apical opening, and at the same time chlorine ions begin 
to collect about the zinc needle, with which they unite to 
produce additional zinc chloride. It will be seen that any 
antiseptic action due to this technic must depend alone upon 
the zinc ions. According to Kronig and Paul the germicidal 
value of a metallic salt depends not only upon its specific 
character, but also upon its electronegative ions. Zinc 
ions as such have no demonstrable antiseptic value, hence if 
they contribute to sterilization it must be that during the 
process of diffusion they unite with certain preexisting 
negative ions in the periapical fluids, to produce a solution 
of an antiseptic salt. 

Prinz's Technic of Ionization. — In the method advocated by 
Prinz, when the current begins to flow sodium ions pass 
through the apical opening, while chlorine ions collect about 
the platinum needle. As platinum is not ionized, the chlorine 
ions unite with each other to form free chlorine, with the 
possible formation of infinitesimal quantities of hydrochloric 
acid as a by-product. In this technic the deposition of sodium 
ions can only add to the abundant supply of those already 
existent in the tissues, therefore the antiseptic value, if any, 
must be dependent upon the chlorine ions. Price claims 
that these have no antiseptic value, but as free chlorine is 
produced in the canal by their union the argument is hard to 
follow. The relative sterilizing value of chlorine thus pro- 
duced, compared to chlorine released from Dakin solution 
irrigations for the same period of time, or from treating with 
chlorinated lime and acetic acid according to the old bleach- 
ing method of Truman, would depend upon the amount of 
free chlorin available by each procedure. 


The Author's Technic of Ionization. — My own practice has 
been a combination of the two methods just studied, using 
zinc chloride as the electrolyte and a platinum needle on the 
positive pole, and thus zinc ions pass through the apical 
opening and free chlorine is released within the canal, Evi- 
dently any therapeutical result which may accrue from either 
is obtained. There is little scientific evidence, however, to 
indicate any inherent sterilizing value in dissociating either 
of the foregoing electrolytes with the amount of current 
which the average patient can bear. 

A third electrolyte which presents a somewhat different 
aspect is Lugol's solution. This consists of iodin crystals, 
5 parts, iodide of potassium 10 parts, and water 100 parts 
by weight. "When the negative electrode is introduced into 
this solution in the canal, the ion I 3 is carried into the peri- 
apical tissues. Iodine as such is not ionized, hence the neces- 
sity for adding iodide of potassium to the solution. In this 
connection the well-proved antiseptic value of tincture of 
iodine should not be mistaken as an index of the value of I 3 . 
However, I am each day becoming more favorably impressed 
with the clinical value of this electrolyte. 

The direct inherent sterilizing value of electrolytic medica- 
tion being so inconsiderable, it would appear that the well- 
recognized clinical benefits following its use must be depend- 
ent upon some change produced in the tissue cells. 

It is reasonable to believe that granulomata persist at 
the root apex without objective symptoms, because the strain 
of streptococcus, which is uniformly conceded to be the infect- 
ing organism, is so low in virulence that inflammatory reaction 
is only passive. The absence of all the classic symptoms of 
inflammation is confirmatory of this belief. 

The vital resistance of living tissue to infection is developed 


and increased by the inflammatory reaction, provided it does 
not proceed to a point of excessive activity. There is a pour- 
ing out into the infected area of white blood cells which have 
the power of ingesting the invading organisms, and of a blood 
plasma of high bacterial power. The inflammatory process 
and repair are very similar and often coincident. 

Electrolytic medication offers an easily controlled means 
i >f thus calling to our aid the defensive forces of nature. While 
the limited antiseptic action of the ions may serve to some 
extent to attenuate the invading organi-ms and thus aid in 
the ultimate result, it is a clinical fact that the use of the 
current is often followed by a varying degree of inflammation, 
signalized by pain. heat, redness, and sometimes swelling. 
The inflammatory reaction may be and often is induced in 
other ways and by other agencies. Indeed it is doubtful if 
the treatment of many cases of periapical disease is carried 
to successful completion without the tooth becoming sore 
at some stage of the treatment, no matter what the technic. 

Controlling the Inflammatory Reaction from Ionization. — The 
inflammatory reaction having been induced must be con- 
trolled. This may be contrived in mild cases by the use of 
counter-irritants, such as iodine, mustard, or capsicum. A 
method which not only tends to control the inflammatory 
process but also ha- a gratifying inhibition on pain symptoms 
is the electrolytic use of Fisher'.- -alt-, as described by Fette. 
A 4 or 5 per cent, solution of magnesium sulphate is applied 
through the apical mucous membrane with the positive 
current. The dosage is about 20 M. a. m. 

The instant there is an indication of exces-ive reaction, 
however, recourse should be had to drainage. The recogni- 
tion of the value of this expedient dates back to Hippocrates 
at least, and this is Nature's own method of fighting pyogenic 


infection. Yet. strange as it may seem, many dentists fail 
to avail themselves of so simple a remedy. The promotion 
of the inflammatory process and the establishment of drainage 
by means of a small window cut through the alveolar plate 
into the cancellous bone of the periapical region will in many 
cases mark the beginning of repair in periapical diseas 


Infected apical cementum presents the most inaccessible 
and troublesome factor in root-canal therapy. For reasons 
already referred to, this dead tissue cannot be bathed in 
chemicals strong enough to destroy the microorganisms, nor 
has it any power of inflammatory reaction. It may be that 
to some extent it is acted upon by the inflammatory exudate, 
or by drugs which inadvertently escape from the canal, but 
if so the effect must be very superficial. Hence, unless the 
denuded area is small enough to be successfully covered in 
the root-filling operation, its surgical removal is indicated. 


1. Xo sterilization of infected teeth can be said to be 
complete unless it includes the canal and tubuli, the denuded 
cementum, and the periapical tissues. 

2. The same agency cannot be depended upon to complete 
sterilization in all these sites. 

The canal and dentinal tubuli can probably be satis- 
factorily sterilized by the thorough use of sodium potassium 
alloy and 30 per cent, sulphuric acid, followed by dressings 
of mild antiseptic oils; or by Howe's silver reduction method. 
4. The periapical region may be sterilized by inducing the 


inflammatory reaction by means of electrolytic medication, 
followed by immediate and sufficient control. 

5. The apical cementum can at best receive but superficial 
sterilization, and unless the denuded portion is small enough 
to be successfully capped with gutta-percha, it must be 
surgically removed. 

6. The establishment of scientifically correct culture 
methods and media is the crying need of the moment. Until 
this is accomplished the filling of the canal must be a proba- 
tionary expedient. 


The leaders of the medical profession are waiting with 
open minds for conclusive evidence that periapical infection 
can be eliminated by root-canal treatment. Meanwhile, 
knowing full well that extraction and curettage will be fol- 

A B 

Fig. 29. — Radiographic'check reasonably co lvincing. 

lowed by a healthy condition of the tissues, it is small wonder 
that many physicians are demanding such treatment for all 
infected teeth. This attitude will continue and increase until 
some tangible method of proving the effectiveness of root- 
canal therapy is available. 

The present dependence upon radiographic check, while 
reasonably convincing in some cases (Fig. 29), requires from 



three to six months for demonstration. In cases attended 
by serious metastatic lesions this interval may be sufficient, 
if periapical infection persists, to so increase the malady that 

Fig. 30. — New bone growth in presence of streptococcus infection filling-in 
area once occupied by resorbed root apex. 

all chances of recovery are lost. This method is further con- 
trovertible on the ground that evidence exists that new bone 

Fig. 31. — New bone growth in presence of infected root apex left in by 
incomplete extraction. Note radiolucent area surrounding fragment. 

growth may occur in the presence of dangerous infection. 
This may be observed where new bone fills in the area once 
occupied by an absorbed root (Fig. 30), or the formation of 


new bone in the alveolus over a root tip left in by fracture 
during extraction (Fig. 31). Even eliminating these objec- 
tions, the check-up method is ineffectual because of the dis- 
inclination of dentists and patients alike to make use of it. 
Hence if we are to have a method of proving the elimination 
of periapical infection which will be universally valuable, it 
must be capable of exhibition prior to filling the root-canal. 

The time has come to give preeminence to this requirement. 
Until the sterility of the tissues can be reduced to demonstra- 
tion the filling of root canals remains an empirical procedure, 
worthy of the condemnation it is receiving in many quarters. 

A study of culture methods and culture media is the foun- 
dation upon which must be builded any attempt to pre- 
determine the successful outcome of root-canal therapy. 


The first difficulty to present is that of obtaining reliable 
material for the culture. Two methods are in vogue. One 
consists in aspirating some of the periapical fluids through 
the root-canal. This method is difficult and its scientific 
value is lessened by the possibilities of contamination. The 
other plan is to gather on the tip of an apexographer or 
platinum broach some of the periapical content by passing 
the instrument through the canal. This method also is open 
to scientific objection in that the material is gathered in a 
direct line with the canal where the greatest force of anti- 
septic treatment is expended, while the little crypts surround- 
ing the area of disturbance are the points most liable to remain 
infected, and these cannot be reached by this method. The 
finding of a negative culture may thus only mean that the 


material has been gathered from a part of the field tempo- 
rarily under the influence of antiseptics. Another possibility 
is that some of the antiseptic used in treatment may remain 
in the canal and be carried over into the culture tube and 
inhibit growth. 

For about four years now the writer has taken cultures 
prior to filling the canal in practically every tooth treated. 
Until recently the technic of obtaining the material for cul- 
ture was as follows: The canal was dried as thoroughly as 
possible with sterile cotton points to absorb any excess of 
antiseptic present. A sterile apexographer was then passed 
through the apical opening until pain was experienced. 
Upon withdrawal the instrument was made to scrape the side 
walls of the canal and then used to inoculate the media. 

For the purpose of checking the value of this method the 
following experiments have been made. In one series of 
cases sterile cotton points were immersed in a sterile 25 per 
cent, solution of glycerin and sealed into the canal with 
gutta-percha, rendered sterile in the flame. These were left 
in place for four days or longer, dependence being placed 
upon the hygroscopic action of the glycerin to induce osmosis 
and thus draw into the cotton the fluids of the periapical 
region. At the following sitting the cotton points were 
removed and dropped into culture tubes. Immediately 
thereafter cultures were made w r ith the apexographer as 
described. In another series of cases similar experiments 
were performed with cotton points saturated with glucose 
broth, thus furnishing a rich pabulum for the propagation 
of any vital bacteria present. There was nothing in the 
results from either of these series to indicate any advantage 
of the cotton points over the apexographer. 

More recently a third series of cases has been tried as fol- 


lows : A culture was first taken by the apexographer method. 
This was followed by aspirating some of the periapical fluid 
into the canal, when a second culture was made by the apex- 
ographer method. The aspirating needle was roughly made 
by soldering a cupped disk of 30-gage platinum plate about 
three-eights of an inch from the end of the platinum point 
of a Berlin abscess syringe, in such a manner that it would 
act as a platform upon which to carry temporary stopping 

Fig. 32. — Aspirating needle to be attached to Elgin casting machine. 

to automatically seal the cavity when the syringe point was 
introduced into the canal. When the temporary stopping 
has hardened the syringe point is connected to the Elgin 
casting machine by means of rubber tubing and about twelve 
pounds negative pressure used. The needle is then withdrawn 
and most of the temporary stopping comes away with it. If 
the apexographer is now passed through the periapical fluid 
which has been drawn into the canal, and on through the 
apical opening until pain is exhibited a most reliable culture 


will be obtained. Based upon twenty cases in which compara- 
tive tests were made, this method is somewhat more efficient 
than the simple apexographer method. 

While it is possible that some more certain method of 
taking the culture may be developed, with such an easy means 
at our command, there is no present justification for an 
empirical acceptance of unreliable clinical evidence in deter- 
mining when the canal is ready for filling. Even though the 
finding of a negative result by this method is not absolute 
evidence of sterility, the finding of a Gram-positive coccus 
is a sure indication that sterilization has not been accom- 
plished, and by this guide alone we shall be prevented from 
filling the canals of many teeth which would otherwise seem 
to justify that procedure. For those who have not taken the 
routine precaution of making cultures prior to root-canal 
filling a surprise is in store, for positive growths will be 
recovered from about 30 per cent, of all cases which give 
every clinical indication of successful termination of the 

Selection of Culture Media. — Next in difficulty only to 
obtaining the culture is the selection of a practicable culture 
media. In the overwhelming majority of cases we have to 
deal with the streptococcus and some media especially 
acceptable to its growth must be selected. 

At the beginning I used an ordinary agar slant. This was 
inoculated with a stab and smear, the idea being to culture 
both the aerobic and anaerobic organisms. Growth developed 
very slowly in these tubes and too large a number remained 
negative. This led to the opinion that sufficient of the anti- 
septic used in canal treatments must be carried over with 
the culture material to cause inhibition. It was, therefore, 
decided to use a liquid culture medium and in such volume 
as to dilute this inadvertent antiseptic to a neutral state. 


Glucose broth was tried, but the large percentage of nega- 
tive results made us suspicious of its efficiency. Besredka's 
egg broth was then employed, and duplicate cultures were 
made for comparison with glucose broth. These experiments 
proved our suspicions to be well founded and the use of 
glucose broth was discontinued. Later the trial of glucose 
broth enriched with human ascitic fluid was suggested. We 
had considerable difficulty in obtaining and keeping this 
medium in a sterile condition and comparative cultures did 
not demonstrate any superiority over the egg broth. 

After using the egg broth for some months, however, there 
was still a feeling of uncertainty, caused by occasional cases 
in which the clinical symptoms were at variance with the 
finding of a negative culture. Dr. Le Comte to whose coop- 
eration in the laboratory is due much of the credit for any- 
thing of value that may be presented here in this connection, 
then suggested the following medium which was quite satis- 
factory : 

1. Human blood dried at 56° C. Pulverize to fine powder 
in mortar. Make solution in distilled water so that it equals 
100 per cent, hemoglobin (Haessler-Felton Scale made by 
Hynson, Westcott & Dunning). Heat at 100° C. in Arnold 
sterilizer; filter clear. 

2. Double strength "Difeo" nutrient broth. 

3. Mix equal parts of Xos. 1 and 2, tube, and sterilize by 
fractional method. 

Each batch is tested before use with several strains of 
streptococci to determine its potency. Then when the new 
batch is used duplicate cultures are made in a few cases to 
determine its relative sensitiveness. It is necessary to stain 
material from the tube in order to determine the presence or 
absence of bacteria. Any bacteria found, other than Gram- 
positive cocci, are considered contaminants and another 


culture made before pronouncing a result. Occasionally a 
culture is made from an undoubted area of active infection 
as a check upon the technic. 

The outcome of these and other experiments in culture 
methods and media has led up to the following technic, 
which gives every indication of reliability. Two cultures are 
taken from each root by means of the combined aspiration- 
apexographer method, and a human plecenta infusion broth 
suggested by Dr. Oscar B. Hunter is inoculated. One of these 
tubes is incubated aerobically and one anaerobically. Sub- 
cultures of any growth resulting are then made upon human 
blood agar plates. 

The length of time allowed for incubation before pro- 
nouncing a negative result is also of great importance. With 
the agar slant we had many cases which remained negative 
until the tenth day. With the ascitic fluid medium we had 
one case which developed growth on the thirteenth day. 
With the egg medium we had one tube develop growth on the 
eighth day and one on the ninth. With the placenta medium 
there has as yet been no case in which growth has begun 
after the sixth day, so that is now being used as the minimum 
time for culture. 

The making of cultures in every case prior to filling the 
canal is not expected to appeal to those who blindly attempt 
to save all infected teeth, nor to those who advise extraction 
in every case. Fortunately for the conservative dentist there 
lies a mid-course in which such precaution will lead toward 

In addition to the streptococcus, which is most frequently 
found, the staphylococcus and diplococcus are also often 
encountered. It is well for the dentist to learn to recognize 
the organisms with which he must deal and a careful study 
of a modern text-book on bacteriology is recommended. 


Provided the root canal has been properly prepared to a 
conical form the filling operation is not one of great difficulty, 
but the question as to the limitation of the filling has created 
considerable discussion. 

^Yhile the theory of blood-borne infection of the peri- 
apical region may be discredited, it is doubtful if it can ever 
be disproved. It follows then that no matter how sterile the 
tissues may be rendered, the filling of the canal must be 
absolute in order to preclude the possibility of reinfection. 
It is preferable in order to emphasize this point to speak of 
obliterating, rather than filling, the canal. Such an operation 
must take into account the dentinal tubuli and accessory 
foramina. There is no such thing as a "pretty good" filling, 
for unless the filling hermetically seals the canal, spaces will 
exist in which bacteria may propagate. 

Let no one delude himself with the idea that he can fill 
any part of the canal or tubuli which has not been previously 
depleted of its organic content. It is in this matter of neces- 
sity that the great value of the use of sodium-potassium is 
manifest. If the dentin has been soaked with an oil readily 
miscible with chloroform an additional advantage will have 
been obtained. 

A number of substances have been suggested for filling the 
dentinal tubuli, of which Callahan's solution of resin in chloro- 


form and Howe's silver-reduction solutions have had the 
widest acceptation. It has been demonstrated beyond 
dispute that these substances will completely penetrate the 
dentin. In view of the well-known facts that the stain from 
a copper-amalgam filling or a base-metal crown post will do 
the same thing, it is strange that such a property required 
demonstration, but penetration and obliteration are entirely 
different propositions. 

There is a hard-pressed filter paper used to filter barium 
salts. The porosities of this paper are about one-tenth the 
diameter of the dentinal tubuli. If a piece of this paper is 
fitted into a funnel and resin varnish poured through it, there 
is no appreciable inhibition to the passage of watery dyes even 
after it has dried. Furthermore, even in the event that it did 
seal the tubuli it would offer no barrier to microorganisms, as 
may be readily demonstrated by the following experiment: 

A number of glass rods, so bent at one end that they may 
be hung up, are dipped into a solution of Bacillus prodigiosus 
and hung up to dry. They are then dipped somewhat deeper 
into chlororesin varnish and allowed to dry again. Petri 
dishes are now inoculated with the varnished end of different 
rods about every fifteen or twenty minutes up to two hours. 
One rod is used unvarnished as a control. After culture it 
will be observed by the uniform amount of the red color 
produced on the medium that the resin varnish has had no 
effect whatever in sealing in the organisms with which the 
rods were coated. If these two experiments are convincing, 
no dependence can be placed in the chlororesin as a filling 

As to Howe's silver reduction method of filling the tubules, 
we need only to perform the reduction in a test-tube to realize 
what occurs in the tooth. When the solutions are mixed the 



walls of the tube become mirrored with silver, but upon 
looking into the tube it will be seen to contain an excess of 
watery solution containing a flocculent precipitate of metallic 
silver, and this is exactly what would exist in any tube no 
matter how small. Substances flow into the dentinal tubuli 
only by capillary attraction, and this physical force is exerted 
upon liquids. 

Until some more convincing evidence is presented for these 
or some other substances for filling the tubuli, it would seem 
wise to place dependence in soaking the dentin with a mild 
antiseptic oil as offering more defense against reinfection 
than is possible by any other present means. 

A B 

Fig. 33. — A, B, multiple canal endings, filled by technic herein described. 

In order to obliterate the accessory foramina and inequali- 
ties of the canal it is necessary that part of the filling material 
should be introduced in liquid form. Chloropercha of proper 
consistence not only will flow into such accessory foramina 
and inequalities as have been opened, but possibly into the 
orifices of the tubuli as well (Fig. 33). The addition of resin 
to the chloroform makes the chloropercha more adhesive 
and it may be used for this purpose. 


After the canal has been made as dry as possible with sterile 
cotton points, a drop of chlororesin is introduced from the 
flamed beaks of the cotton pliers and pumped into the canal 
with a smooth broach. A gutta-percha point considerably 
smaller than the canal is now pushed into it and agitated in 
such a manner that it is dissolved, thus forming chloropercha 
within the canal. This is the method suggested by Callahan 
and leaves nothing to be desired. 

The bulk of the filling may be made of undissolved gutta- 
percha. This is not an absolutely ideal material for root- 
canal filling, but has more points in its favor than any other 
material proposed for this purpose. When properly intro- 
duced and condensed it serves the clinical requirements. 

The most satisfactory form for routine use is the so-called 
"points" or, more properly speaking, cones. Those prepared 
by the Mynol Company are comparatively uniform and free 
from inequalities. They are also flattened on the end, which 
makes them easier to grasp in the cotton pliers. 


Since the necessity for completely filling all canals has 
become an accepted policy, the desire of conscientious men to 
surely accomplish this end has led in many instances to 
grotesque overfilling, which at best serves no useful purpose 
(Fig. 34). Granted that in many cases this causes no par- 
ticular damage other than a temporary trauma, nevertheless 
in lower molars and bicuspids a periapical projection of gutta- 
percha may impinge on the mandibular nerve, and in upper 
bicuspids and molars a piece of gutta-percha extending into 
the antrum would surely invite reinfection (Fig. 35) . 

The amount of filling material, if any, which should be 


Fig. 34. — Grotesque overfilling. 




A B 

Fig. 35. — A, gutta-percha point, probably projected into antrum; B, 
gutta-percha point impinging on inferior dental nerve, causing sensory 
paralysis of lower lip. 


Fig. 36. — A, crater at apex should be filled; B, apex should be capped; 
C, too much dead cementum to be capped. 


forced through the apical opening depends upon the extent 
to which the apical cementum has been denuded of its life- 
giving membrane (Fig. 36). In a very few cases of Class I 
and in all cases in which there is as yet no periapical disturb- 
ance the line of the pericementum as disclosed by the radio- 
graph is practically continuous. In such teeth to be ideal the 
filling should stop at the apical extremity of the canal (Fig. 
37 .4 and Fig. 43). 

A careful examination of the apical termination of the canal 
in a number of extracted teeth will reveal the fact that in a 
goodly proportion there exists a crater-like depression in the 

Fig. 37. —A, filled to the end; B, crater filled; C, apex capped. 

cementum at this point. This should be considered an 
integral part of the canal in so far as the filling operation is 
concerned, except in cases of recent operative devitalization. 
The radiographic evidence of the filling of this crater would 
indicate a little ball at the root apex (Fig. 37 B and Fig. 38). 
In no case is it necessary or even desirable to project a 
solid gutta-percha point beyond the root end, but wherever 
denuded apical cementum exists the attempt should be made 
to cover this with a cap-like film of chloropercha (Fig. 37, C). 
A careful study of the radiograph will indicate the amount 
of filling material which will be of value beyond the canal 



proper, and by different methods of inserting the filling about 
to be explained this amount can be controlled to a reasonable 

C D 

Fig. 38. — Crater filled. Correct technic only in cases of pulp decomposi- 
tion, attended with no periapical disturbance. 


The method of filling just to the end is as follows: In 
preparing the canal for this purpose the apical foramen 
should not be enlarged. The canal is flooded with chloro- 
resin varnish and a very fine cone introduced and passed 
toward, but not quite to, the root end. This is dissolved with 
a stirring, not a pumping motion, which will coat the canal 


walls with a sticky chloropercha. A somewhat larger cone 
is now selected, but not so large as to impinge on the canal 
walls in its passage to the apex. This is dipped in chloro- 
resin and slowly insinuated into the canal almost to the end. 
At this stage time must be allowed for the chloroform to 
dissipate before proceeding with the operation. Part of the 
chloroform will evaporate and part will combine with the 
gutta-percha of the cone. As this process progresses the 
chloropercha becomes thicker and the gutta-percha cone 
becomes softer until at last the whole mass in the apical end 
of the canal will be homogeneous. When the gutta-percha 
in the pulp chamber is about the consistence of unvulcanized 
rubber a blunt plugger, too large to go far into the canal, is 
slightly warmed and used to gently pack the filling material 
toward the apex. At the first suggestion of pain the packing 
should cease. A fine plugger which will freely pass into the 
canal is now warmed and carefully passed through the center 
of the mass until it enters the apical third of the canal. It is 
then moved about in such a manner that the filling material 
is packed against the side walls of the canal, after which the 
deficiency thus caused is filled with a suitable cone packed 
to place. This procedure should be repeated until the canal 
is full. 

If the radiograph shows the filling to be incomplete, this 
can be corrected at a subsequent sitting by placing a drop of 
chloroform in the pulp chamber and passing a root pick 
through the filling toward the apex until pain is experienced. 
The opening thus made is then filled with a suitable gutta- 
percha point first dipped in chloroform 

To prevent overfilling the following points should be 
observed : 

1. Do not enlarge the apical opening. 


2. Use a stirring motion in making the chloropercha. 

3. Insert the cone in such a manner as not to force the 
chloropercha ahead of it. 

4. Patiently wait for the whole mass in the apical end of 
the canal to become homogeneous before beginning to pack. 

5. Discontinue packing toward the apex at the first indi- 
cation of pain. Thereafter pack against the side walls only. 


In order to cap a denuded root apex, and this is necessary 
in most cases of periapical disease, the apical foramen should 
be somewhat enlarged. Too much zeal in this direction, how- 
ever, will result in a persistent seepage into the canal, which 
is most difficult to control. 

The capping of a denuded apex is usually much easier than 
filling just to the end, and the amount of filling material 
extruded can be controlled to a reasonable degree (Fig. 39). 

Depending upon the amount of capping desired, the canal 
should be lined or even filled with chloropercha in the manner 
previously described, only now the cone should be dissolved 
by a pumping motion, as many cones and as much chloro- 
resin being used as may be necessary to furnish a suitable 
amount. A little experience will soon equip the operator to 
judge this with a fair degree of accuracy. A cone which 
approximately fits the canal is then selected and dipped in 
chlororesin, and gently pumped through the chloropercha 
to the end of the canal. During these pumping operations 
there will often be slight twinges of pain, but these are caused 
by the irritation of the chloroform and should be disregarded. 
When the cone finally seems to have reached the end of the 
canal, time must be allowed as before for the chloroform to 



diffuse, but it is not necessary to wait quite so long as when 
the filling is to be confined to the canal. Usually when the 
blunt end of the cone begins to be plastic the point will not 
be solid enough to penetrate tissue. If pressure is then 
brought to bear, the mass in the apical end of the canal will 

C D 

Fig. 39. — Apex capped. Correct technic only in cases attended with 
exposed apical cementum. 

flow through the apical opening at such a consistence as to 
distend the granulation tissue and flow in the direction of the 
least resistance. In other words, it will fill the space where 
tissue is missing. It is possible that the natural elasticity of 
the granulation tissue will have a tendency to force this 
gummy mass back toward the denuded cementum, thus 


increasing the intimacy of its attachment. This may be 
further assisted by making pressure on the crown of the tooth 
with the finger, or better by allowing the patient to bite hard 
with the tooth on an ordinary lead-pencil eraser. The well- 
known tendency of chloropercha to shrink upon the evapora- 
tion of the chloroform will result in a properly placed capping 
hugging the root apex tighter than ever. 

The amount of filling material passed through the apical 
opening may be controlled as follows: 

1. The degree to which the apical opening is enlarged. 

2. The amount of chloropercha formed in the canal. 

3. The gradation of the pumping motions, both in making 
the chloropercha and inserting the filling. 

4. The accuracy of the fit of the gutta-percha cone. 

5. The consistence of the mass in the apical end of the canal 
when pressure is brought to bear. 

If pressure is exerted too soon, the liquid chloropercha will 
be forced into the meshes of the granulation tissue by the 
piston-like action of the cone (Figs. 40 and 41); or the point 
of the cone may be so solid as to penetrate the chloropercha 
cap (Fig. 42). Only when the filling material is gummy may 
it be confined between the granulation tissue and the cemen- 
tum. By careful study of the foregoing features it will be 
possible in most instances to confine the extruded filling 
material to the immediate utility of capping the root apex. 

When the root apex is capped the packing of the filling 
against the side walls of the canal should be done as previously 
described, and then the whole mass forcibly packed with a 
warm plugger, too large to go far into the canal. If pain is 
exhibited during the packing more time should be allowed 
as this is an indication that the gutta-percha cap is still soft 
enough to flow. A few teeth thus capped have been extracted 



several months after the insertion of the fillings. In these 
cases the cap was very adherent to the cementum and about 
as hard as gutta-percha becomes in coronal cavities. 

v J V. J 

Fig. 40. — Filling in mesial root caps Fig. 41. — Runaway chloropercha 

a large denuded area of apical cemen- 
tum. Filling in distal root projected 
by too precipitate pressure forcing 
the chloropercha ahead by its piston- 
like action. 

resulting from pressure on cone while 
chloropercha was too fluid. Note 
beautiful result in distal root, in 
which the chloropercha became 


Fig. 42. — Solid gutta-percha point penetrating the chloropercha cap. 
(Distobuccal root.) 


Before leaving the subject of the treatment of root-canals 
to consider the surgical treatment of periapical disease, it 
may be wise to consider the subject of devitalization of unin- 
fected teeth. 



For many years the dental profession ignorantly destroyed 
normal pulps in order to make bridge abutments more secure. 
The disclosures of the dental radiograph of periapical coli- 

cs D 

Fig. 43. — Canals filled to the end. Correct technic only in recently 
devitalized teeth. 

ditions which supervened gave such a shock to the profession 
that the conscientious dentist now looks with fear and tremb- 
ling upon the necessity for such an operation. Yet until some 
more satisfactory abutment for vital teeth is devised, the de- 


mand of an educated public for removable bridge work will 
continue to make devitalization necessary. In view of the 
holocaust wrought by this agency in the past, how may it now 
be undertaken with safety? The crux of the whole matter 
lies in asepsis. Provided the pulp may be extirpated and the 
canal obliterated without introducing infection no untoward 
result should follow. Teeth are not a source of danger because 
they are pulpless but because they are infected. With the most 
painstaking technic a tooth once infected may be rendered 
safe, but the aseptic devitalization and filling of non-infected 
teeth offers the greater sense of security. 

As in any surgical operation of choice, the prime considera- 
tion is the selection of cases in which conditions will not fore- 
stall a happy termination. Teeth with deep-seated decay or 
pyorrhea or those in close proximity to periapical areas of 
infection should be avoided. Preference should be given to 
teeth with unbroken enamel covering. The extirpation of 
pulps accidentally exposed in operating should be delayed 
until a mild antiseptic dressing has been sealed in contact 
with the pulp for a couple of days. 


With the strictest aseptic technic the pulp chamber is 
uncovered and all debris cleaned away with alcohol. A fine, 
smooth broach is used to explore the canal. The pulp is 
extirpated with a fine Donaldson pulp-canal cleanser. This 
should be insinuated in the path made by the smooth broach 
until it appears to have reached the apex. It is then with- 
drawn just a trifle to avoid the possibility of binding and 
twisted around slowly a couple of times. The sense of touch 
will be more acute if no broach holder is used. When the 


broach is withdrawn the pulp will usually be found twisted 
about it. If only part of it comes away the remainder will 
be removed during the enlarging and shaping of the canal 
by the technic previously described. 

Repeated washings with hydrogen peroxide, using the 
sterile cotton points or cotton wrapped broaches as swabs, 
will remove all the blood and debris and leave the canal walls 
clean. An apex curette is then used to clean the extreme end 
of the canal, but no instrument must pass through into the peri- 
apical tissues. The canal is again washed with hydrogen- 
perioxide and dried as thoroughly as possible with cotton 

A strand of picture wire, wrapped with cotton fibers and 
placed in apinol prior to the operation, is now passed into the 
canal and sealed there with gutta-percha rendered sterile 
in the flame. A radiograph is made and studied as a guide to 
the length of the root. 

Xo attempt should be made to fill the canal while anes- 
thesia persists for fear of overfilling, which in such cases is 
entirely undesirable. Indeed, it is less dangerous to fall 
slightly short of the apical extremity than to have the filling 
protrude into the periapical tissues (Fig. 40). 

For the extirpation of vital pulps slow subperiosteal injec- 
tions of cocain immediately over the root apex will generally 
be satisfactory, but in bicuspids and molars it is often well 
to support this with conduction anesthesia. Pressure anes- 
thesia is responsible for much of the infection which has 
followed extirpation, because the possibilities of contami- 
nation are infinite. It is wiser to avoid it entirely, but if 
employed some of the anesthetics which will stand boiling 
should be used and base-plate gutta-percha softened in the 
flame should be substituted for red vulcanite rubber as a 


Many infected teeth which fail to respond to root-canal 
treatment, as well as those which the diagnosis eliminates as 
unfavorable for the attempt, may be saved by surgical pro- 
cedure. As any surgical operation is rendered more certain 
of successful termination when performed under satisfactory 
anesthesia, a word upon that subject may not be amiss. 

Conduction anesthesia raises dentistry to the nth power, 
yet many will not take the pains to thoroughly master the 
comparatively simple technic. There are a number of books 
published which place this modern method within the easy 
reach of all. For any surgical interference in the periapical 
region it at once furnishes a prolonged anesthesia, and avoids 
the possibility of scattering the infection. 

For root resections, in addition to conduction anesthesia, 
there should be an extremely slow infiltration of novocain 
solution rich in suprarenin immediately under the apical 
periosteum. This will make anesthesia more prompt and 
give a comparatively bloodless operation. 


As previously stated the establishment of periapical drain- 
age is often a valuable aid in root-canal procedure. Depend- 
ence upon antiseptics to accomplish in the mouth that which 


has proved to be impossible in other parts of the body will 
lead only to failure. Success lies in a more universal adoption 
of surgical principles. 

To establish periapical drainage a horizontal incision 
about half an inch in length is made over the root end. The 
soft tissues are reflected upward and downward exposing 
the alveolar plate. With small sharp chisels a window is then 
made about one-eighth of an inch in diameter, exposing the 
cancellous bone. With a stiff sharp probe punctures are 
made to the root end, thus permitting drainage. The lips 
of the wound should be prevented from uniting by means of a 
gauze wick changed daily, until all discharge ceases. This 
treatment is indicated whenever the inflammatory reaction 
becomes excessive and in all pus cases whether acute or 


It is improbable that any periapical infection which has 
once reached the stage of pus formation or liquefaction of 
tissue can long persist without destruction of the apical fibers 
of the pericementum. Proliferating infections have the same 
result and in the presence of much dead apical cementum 
thus produced little is to be expected of medicinal treatment. 
We may heal the sick but we cannot raise the dead, and an 
infected necrotic area calls for surgical interference. 

Root resection is not a panacea for all teeth with peri- 
apical areas of infection. In selected cases, however, it gives 
a reasonable percentage of successes. It is unwise to attempt 
it in teeth whose gingival cementum has been exposed to any 
extent by pyorrhea, or in teeth which cannot be freed of the 
odor of putrefaction. Several days prior to the operation, 


the canal should be opened as thoroughly as possible, and 
treated by Howe's silver reduction method or a dressing of 
formocresol. Powerful and escharotic drugs may here be 
used, as any tissue which may be deleteriously affected is to 
be surgically removed. Just prior to the operation the canal 
should be filled w r ith copper amalgam, using the utmost care 
to secure a thorough condensation. 


An aseptic operation is possible and desirable. The 
patient's head should be covered with a sterile cap and the 
chest and shoulders covered with sterile towels. A folded 
sterile towel should be laid over the eyes and nose and another 
across the chin under the lower lip, and both secured to the 
cap with safety pins. An oblong sponge made by sewing a 
wad of absorbent cotton in a small J. & J. napkin is now 
placed between the jaws and the patient instructed to close 
the teeth upon it. This w T ill serve to absorb saliva and blood 
and make the use of a saliva ejector unnecessary. A square 
of gauze folded once on the bias is now placed over the nos- 
trils and under the upper lip, the free ends being tucked 
under the towel which covers the eyes. The teeth and 
mucous membrane in the neighborhood of the infection are 
now rubbed dry with gauze to remove the mucus, and the 
whole field painted with tincture of iodin. It is understood, 
of course, that the hands of the operator and assistant have 
been sterilized and that sterile gowns, or at least sleeves, are 
worn; also that all instruments used are sterile and handled 
in an aseptic manner. 



The incision should be made rather low, that is to say, 
below the line of the alveolar-labial juncture, and should be 
from a half to three-quarters of an inch in length. It should 
be made straight and the point of the knife should sink to 
the bone so as to incise the periosteum. By blunt dissection 
the mucoperiosteum is freely loosened from the bone, upward 
and downward. The labial flap should be retracted. This 
may be done with a fork retractor, but the method advanced 
by Sausser of passing a silk suture through the edge of the 
flap and making a loop of this to retract the tissue is often 
more satisfactory and causes less traumatism. The blood 
should now be sponged away by the assistant until the wound 
is dry enough to give a clear view of the condition of the 
alveolar plate. This may be intact or may have undergone 
any degree of disintegration depending upon the type of 
disease present. In cyst cases it will often be thinned out 
to a parchment-like consistence. In Class II cases it will 
often be cheesy and discolored. Whatever its condition a 
sufficient amount should be removed to assure ready access 
to the root apex. If the bone is normal this is best done with 
a bone gouge and mallet. The operator should direct the 
gouge, while the assistant uses the mallet. Where the bone 
is softened or thinned out, the window may be nicely made 
with large spoon excavators. 

The field should be again dried of blood and the periapical 
condition studied. Usually the infected tissue which invests 
the root apex will now be disclosed to view. In cases of Class 
I and Class II it will appear as a velvet-like mass of granula- 
tion tissue. This should be thoroughly curetted away with 
small curettes or large spoon excavators. The wound is then 


washed out with small sponges soaked in Ringer's or physio- 
logical salt solution, exposing the root apex to careful exami- 
nation. Not infrequently the infected tissue will lie lingually 
to the root apex, in which case the root apex must be resected 
before the soft tissue can be curetted. 

When the disease is of Class III, upon the removal of the 
overlying thin plate of bone, the cyst wall will be readily 
recognized by its homogeneous structure and yellow or 
bluish-gray color. The attempt should be made to enucleate 
the cyst in its entirety without rupture. In order to accom- 
plish this it is essential that the window in the alveolar plate 
should be made large enough for its passage. The thinned 
portion of the bone may be readily lifted out with spoon 
excavators but the thicker bone surrounding must be cut 
away with bone gouges and mallet until the full extent of the 
cyst is visible. The root apex is now resected just below the 
point of attachment of the cyst wall. By careful blunt dis- 
section the cyst may now be freed from its bony capsule and 
removed unbroken. Suitable blunt dissectors for this work 
may be selected from the ordinary amalgam instruments. 

In cases of Class I and Class II the apex should be resected 
just coronally to the point where healthy pericementum 
begins. This will be indicated by intimate contact between 
the bone and root. The best instrument to use for this pur- 
pose is the cross-cut fissure bur. Chisel and mallet have been 
advised, but these do not permit of the same nicety of con- 
trol as does the bur. If an amalgam filling in the stump is 
desired the cut should be made in such a manner that the 
stump is shorter labially than lingually. This will facilitate 
the preparation of the cavity. After the apex has been 
removed, the whole diseased area should be curetted down 
to healthy bone. In some cases of Class II projections of 



granulation tissue will be found extending from the central 
mass into the bone in various directions. These should all 
be followed up until no vestige of abnormal tissue remains. 
The cavity thus made is again washed out with wet sponges 
and then packed firmly with dry gauze until hemorrhage is 

Fig. 44. — Some ragged amalgam fillings. 

A final inspection is now made for diseased tissue which 
may remain, and assurance that every vestige of necrotic 
cementum has been removed. ^Yhen the wound is clean, 
the cavity for the amalgam filling may be prepared with 
inverted cone burs, starting at the canal and working to the 
cementum. Much skill is necessary to confine the amalgam 
within the cavity, and often the edges of the filling will be 
ragged and small particles will fall into the wound from which 
it is practically impossible to recover them (Fig. 44). There 
is considerable difference of opinion as to the advantage of 
this procedure and after three years' trial, I have abandoned 
it in favor of the following method : The root stump is dried 
and carefully painted with a saturated solution of silver 
nitrate, being careful to avoid contact with the surrounding 


tissue. The cut surface of the dentin is then thoroughly 
burnished with a silver burnisher and the wound washed out 
with salt solution. 


Before closing the wound a careful examination should be 
made to be certain that no foreign body, such as sponges, 
scraps of amalgam or bone chips, remains. In case of Class 

111 where the cyst has been enucleated without rupture, pro- 
vided asepsis has been maintained, the wound may be imme- 
diately completely sutured. In other cases, however, it 
seems more in keeping with surgical principles to only par- 
tially suture the wound, leaving space for the insertion of a 
gauze wick for drainage. 

The wound should be closed by interrupted sutures of 
black silk and these may be removed on the fourth or fifth 
day. Where indicated, drainage should be maintained until 
the wound will no longer retain the gauze. This will require 
that the patient be kept under observation for a month or 
even longer. A radiograph should be made soon after the 
operation and another, after six months or more have 
elapsed (Fig. 45) . A regeneration of bone will be indicative 
of a successful outcome (Fig. 46) . 

Technic of Tooth Bisection. — Molar teeth are often extracted 
because one root is hopelessly diseased, although the other 
root or roots may be curable. If such a tooth can be made 
valuable by a crown or used as an abutment for bridge work 
it is generally worth saving by tooth bisection (Fig. 47). 

In preparing a tooth for this operation the root which is to 
be eliminated ; should have its canal dressed with formo- 
cresol sealed in with permanent cement. This will prevent 
contamination of the other canal or canals while they are 



Fig. 45. — A good result with amalgam filling: A, few days after root resec- 
tion; B, same, one year later. 

f — ZZ 


Fig. 46. — Apparent bone regeneration about resected roots (new technic) ; 
A, a few days after root resection; B, same, four months later. 


A B 

Fig. 47. — Examples of tooth bisection. 


being treated and filled. A good radiograph made after the 
root filling will be of great assistance in planning the operation. 
Straight incisions should be made in the buccal and lingual 
gum from the gingiva at the point of bifurcation toward the 
root end, about one-eighth of an inch. Deflecting the soft 
tissues the tooth is bisected with a pointed cross-cut fissure 
bur. The cutting should begin in the bifurcation and proceed 
coronally. It is more satisfactory when this can be done by 
cutting from one side only, but it generally will be necessary 
to cut alternately from the two points of incision. If the 
bisection does not start exactly at the point of bifurcation a 

Fig. 48. — Spike left by failure to start bisection exactly at point of 

small spike of root will be left which will make the tooth 
permanently tender (Fig. 48). The cutting should continue 
through the crown including all that part which is imme- 
diately supported by the diseased root. When completely 
severed, the root may be extracted, and the socket curetted 
and wiped out with tincture of iodin. The portion of the 
tooth which remains should now be made as smooth as 
possible subgingivally, which completes the operation. 

In crowning bisected teeth it is best to cut them off to the 
gingiva and use post and plate crowns with an occlusal rest 
on the tooth proximal to the missing root. 


Accessory foramina, filling of, 91 
Alveolar abscess, 33 

microorganisms of, 34 
radiograph of, 33 
Amalgam filling in root resection, 

Anatomical considerations, 34 
Anesthesia, conduction, 104 

for divitalization, 103 
Antrum of Highmore, canal open- 
ing in, 36-38 
dental films of, 38 
Apexographer, 47 

method of using, 63 
Apical opening, enlarging of, 63 
Asepsis, 41 

difficulty of, in dentistry, 41 
for surgical operations, 106 
wounds, 19 
Aspirating periapical fluids, 85 

Banding teeth to hold rubber dam, 

Bisection of teeth, 110 

indications for, 1 10 

preparatory treatment for, 110 

technic of, 112 
Blood borne infection, 89 
Bloodless operations, 104 
Bone growth in infection, 82 
Broaches, method of keeping,45-48 
Broken instruments in canal, 57 

Callahan's method of introducing 
chloropercha, 92 


Callahan's method of introducing 
solution of resin, 90 
sulphuric acid, 55 
Canals, exploration of, 53 
locating, 52 

number and location, 52 
Capping root apex, 97 
Case history, 24 
Cavity of access, 50 
Cementum, exposed or roughened, 
perforation of, 38 
infected, 79 
Chip blower, method of using, 63 
Classification of periapical disease, 

Color test, 20 
Coriell cannula, 40 
Cotton rolls, use of, 48 
Crane canal openers, 54 
Culture media, 87-88 
methods, 83 

experiments in, 84 
value of, 86-88 
Curettage after extraction, 32-81 
Curved root method of enlarging, 64 

of exploring, 59 
Cyst, dental, 27 

enucleation of, 32 
histopathology of, 33 
operation for, 108 
prognosis in, 33 
radiograph of, 32 

Dakin solutions, 69 
Dental cyst, 27 

operation for, 108 
Destruction of alveolar bone, 23 



Devitalization, dangers of, 101 

technic for, 102 
Diagnosis, definition of, 20 

differential, 27 

physical, 20 
Diagnostic wire, 58 
Dichloramin-T, 70 
Disinfection of dentine, 67 
Drainage, 78 

technic for, 104 


Electrical test for vitality, 21 
method of making, 22 

Electrolyte, 72 

Electrolytic medication, 73 
Crane's technic of, 77 
Fette's technic of, 75-76 
limitations of, 75 
Prinz's technic of, 75-76 

Enlarging canal, 53 

Exploring canal, 53 

Extraction, indications for, 36 

Favorable prognosis, 38 
Filling canal to the end, 95 
Finding the canal, 52 
Fisher's salts, electrolytic use of, 78 
Formocresol, 68-71 

Granuloma, advanced, 27 
histopathology of, 30 
operation for, 108 
primary, 27 
prognosis in, 30-32 
radiograph of, 27-31 
Gutta-percha as root filling, 92 
method of dissolving, 57 
Mynol points, 92 

Howe silver as root filling, 90 
Hydrogen peroxide, method of 
using, 63 

Incomplete root filling, 39-89 

correction of, 96 
Incubation, 88 

Infection without radiographic evi- 
dence, 24 
Inflammatory reaction, 78 
control of, 78 

excited by electrolytic medica- 
tion, 78 
Instrumentarium, 47 
Ionization, 71 
Ions, movement of, 72 

Kerr root canal files, 47-61 
method of using, 62 
probes, 53 

Lamina dura, 24 

absence of, 30 
Limitation of canal filling, 94 
Lugol's solution, 77 


Normal tooth, radiograph of, 24 

High frequency current test, 22 
Howe silver method, 68 

Operating table, 46 

setting of, 47 
Overfilling the canal, 92 

Paraffine pellets, 49 
Pathfinder, Twentieth century, 53 



Percussion test, "dull note," 23 

Talbot's, 23 
Perforation of cementum, 39 
Periapical disease, 26-65 

areas of infection in, 66 
Pericementum, infected, 26 

normal, 24 
Prognosis, favorable, 39 

unfavorable, 36 
Protection of exposed dentin, 21 
Pulp chamber, preserving walls of, 


Radiolucext areas, 27 
Radioparent areas, 27 
Rarefying osteitis, 30 

without infection, 25 
Removing canal fillings, 60 
Rhein canal enlargers, 47 
root picks, 47-53 

method of using, 55 
Root resection, preliminary treat- 
ment of, 106 
postoperative treatment of, 

suturing in, 110 
technic of, 107 
value of, 105 
Rubber dam, adjustment of, 42 


Schreier's paste, 56 
Short handled broaches, method of 
keeping, 48 
of using, 48 
Silver nitrate treatment, 69 
in root resection, 109 

Sodium-potassium, 56 

value of, in root filling, 89 
Standardization, 18 
Sterile packages, 43 
Sterilization of apical cementum, 80 

of broaches, files, etc., 45 

of coronal dentin, 42 

of cotton and dressings, 43-44 

of gutta-percha points, 49 

of infected dentin, 70 

of instruments, 45 

of operative field, 42 

of periapical region, 71 
Sterilizer, high pressure, 45 

Pentz, 45 
Suturing in root resection, 110 

Thermal test, 23 
Tooth bisection, 110 
Translucency test, 20 

Unfavorable prognosis, 36 

X-ray, anatomical considerations 
in, 34 
check-up, 81 

classification of periapical dis- 
ease, 27 
interpretation, 24 
Xylol, 52-57